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  • 1.
    Biswas, Srijit
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Dahlstrand, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Watile, Rahul A.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Kalek, Marcin
    Himo, Fahmi
    Samec, Joseph S. M.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Atom-Efficient Gold(I)-Chloride-Catalyzed Synthesis of alpha-Sulfenylated Carbonyl Compounds from Propargylic Alcohols and Aryl Thiols: Substrate Scope and Experimental and Theoretical Mechanistic Investigation2013In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 19, no 52, p. 17939-17950Article in journal (Refereed)
    Abstract [en]

    Gold(I)-chloride-catalyzed synthesis of -sulfenylated carbonyl compounds from propargylic alcohols and aryl thiols showed a wide substrate scope with respect to both propargylic alcohols and aryl thiols. Primary and secondary aromatic propargylic alcohols generated -sulfenylated aldehydes and ketones in 60-97% yield. Secondary aliphatic propargylic alcohols generated -sulfenylated ketones in yields of 47-71%. Different gold sources and ligand effects were studied, and it was shown that gold(I) chloride gave the highest product yields. Experimental and theoretical studies demonstrated that the reaction proceeds in two separate steps. A sulfenylated allylic alcohol, generated by initial regioselective attack of the aryl thiol on the triple bond of the propargylic alcohol, was isolated, evaluated, and found to be an intermediate in the reaction. Deuterium labeling experiments showed that the protons from the propargylic alcohol and aryl thiol were transferred to the 3-position, and that the hydride from the alcohol was transferred to the 2-position of the product. Density functional theory (DFT) calculations showed that the observed regioselectivity of the aryl thiol attack towards the 2-position of propargylic alcohol was determined by a low-energy, five-membered cyclic protodeauration transition state instead of the strained, four-membered cyclic transition state found for attack at the 3-position. Experimental data and DFT calculations supported that the second step of the reaction is initiated by protonation of the double bond of the sulfenylated allylic alcohol with a proton donor coordinated to gold(I) chloride. This in turn allows for a 1,2-hydride shift, generating the final product of the reaction.

  • 2.
    Biswas, Srijit
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Samec, Joseph
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    A Gold(I)-Catalyzed Route to α-Sulfenylated Carbonyl Compounds from Propargylic Alcohols and Aryl Thiols2012In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 48, no 52, p. 6586-6588Article in journal (Refereed)
    Abstract [en]

    A one-step atom efficient gold(I)-catalyzed route to α-sulfenylated ketones and aldehydes from propargylic alcohols and aryl thiols is described.

  • 3.
    Biswas, Srijit
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Samec, Joseph
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    The Efficiency of the Metal Catalysts in the Nucleophilic Substitution of Alcohols is Dependent on the Nucleophile and Not on the Electrophile2013In: Chemistry - An Asian Journal, ISSN 1861-4728, E-ISSN 1861-471X, Vol. 8, no 5, p. 974-981Article in journal (Refereed)
    Abstract [en]

    In this study, we investigate the effect of the electrophiles and the nucleophiles for eight catalysts in the catalytic SN1 type substitution of alcohols with different degree of activation by sulfur-, carbon-, oxygen-, and nitrogen-centered nucleophiles. The catalysts do not show any general variance in efficiency or selectivity with respect to the alcohols and follow the trend of alcohol reactivity. However, when it comes to the nucleophile, the eight catalysts show general and specific variances in the efficiency and selectivity to perform the desired substitution. Interestingly, the selectivity of the alcohols to produce the desired substitution products was found to be independent of the electrophilicity of the generated carbocations but highly dependent on the ease of formation of the cation. Catalysts based on iron(III), bismuth(III), and gold(III) show higher conversions for S-, C-, and N-centered nucleophiles, and BiIII was the most efficient catalyst in all combinations. Catalysts based on rhenium(I) or rhenium(VII), palladium(II), and lanthanum(III) were the most efficient in performing the nucleophilic substitution on the various alcohols with the O-centered nucleophiles. These catalysts generate the symmetrical ether as a by-product from the reactions of S-, C-, and N-centered nucleophiles as well, resulting in lower chemoselectivity.

  • 4.
    Biswas, Srijit
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Samec, Joseph S. M.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Gold-catalyzed route to alpha-sulfenylated carbonyl compounds from propargylic alcohols and thiophenol: Scope, limitations, and mechanism2013In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 245, p. 382-ORGN-Article in journal (Other academic)
  • 5.
    Biswas, Srijit
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Watile, Rahul A.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Samec, Joseph S. M.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Tandem Pd/Au-Catalyzed Route to alpha-Sulfenylated Carbonyl Compounds from Terminal Propargylic Alcohols and Thiols2014In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 20, no 8, p. 2159-2163Article in journal (Refereed)
    Abstract [en]

    An efficient and highly atom-economical tandem Pd/Au-catalyzed route to -sulfenylated carbonyl compounds from terminal propargylic alcohols and thiols has been developed. This one-step procedure has a wide substrate scope with respect to substituents at the -position of the alcohol. Both aromatic and aliphatic thiols generated the -sulfenylated carbonyl products in good to excellent yields. A mechanism is proposed in which the reaction proceeds through a Pd-catalyzed regioselective hydrothiolation at the terminal triple bond of the propargyl alcohol followed by an Au-catalyzed 1,2-hydride migration.

  • 6.
    Blom, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Light-Triggered Conformational Switches for Modulation of Molecular Recognition: Applications for Peptidomimetics and Supramolecular Systems2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The main focus of this thesis is on photochemical modulation of molecular recognition in various host-guest systems. This involves the design, synthesis and integration of light-triggered conformational switches into peptidomimetic guests and molecular tweezer hosts. The impact of the switches on guest and host structures has been assessed by spectroscopic and computational conformational analysis. Effects of photochemical structure modulation on molecular recognition in protein-ligand and supramolecular host-guest systems are discussed.

    Phototriggerable peptidomimetic inhibitors of the enzyme M. tuberculosis ribonucleotide reductase (RNR) were obtained by incorporation of a stilbene based amino acid moiety into oligopeptides between 3-9 residues long (Paper I). Interstrand hydrogen bond probability in the E and Z forms of the peptidomimetics was used as a tool for predicting conformational preferences. Considerable differences in inhibitory potency for the E and Z photoisomers were demonstrated in a binding assay.

    In order to advance the concept of photomodulable inhibitors, synthetic routes towards amino acid derivatives based on the more rigid stiff-stilbene chromophore were developed (Paper II).  The effect of E-Z isomerization on the conformational properties of peptidomimetic inhibitors incorporating the stiff-stilbene chromophore was also assessed computationally (Paper III). It was indicated that inhibitors with the more rigid amino acid derivative should display larger conformational divergence between photoisomers than corresponding stilbene derivatives.

    Bisporphyrin tweezers with enediyne and stiff-stilbene spacers have been synthesized, and the conformational characteristics imposed by the spacers have been studied and compared to a glycoluril linked tweezer. The effects of spacers on tweezer binding of diamine guests and helicity induction by chiral guests have been investigated (Paper IV). Connections between spacer flexibility and host-guest binding strength have been established. The structural properties of the stiff-stilbene spaced tweezer made it particularly susceptible to helicity induction by both monotopic and bitopic chiral guests. Finally, the possibility of photochemical bite-size variation of tweezers with photoswitchable spacers has been assessed. Initial studies have shown that photoisomerization of the tweezers is possible without photochemical decomposition. Conformational analyses indicate that isomerization should impact binding characteristics of the tweezers to a significant extent (Paper V).

    List of papers
    1. Phototriggerable peptidomimetics for the inhibition of Mycobacterium turberculosis ribonucleotide reductase by targeting protein-protein binding
    Open this publication in new window or tab >>Phototriggerable peptidomimetics for the inhibition of Mycobacterium turberculosis ribonucleotide reductase by targeting protein-protein binding
    Show others...
    2015 (English)In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 13, no 9, p. 2612-2621Article in journal (Refereed) Published
    Abstract [en]

    Incorporation of an artificial amino acid 2 with a stilbene chromophore into peptidomimetics with three to nine amino acids yields phototriggerable candidates for inhibition of the binding between the R1 and R2 subunits of the M. tuberculosis ribonucleotide reductase (RNR). Interstrand hydrogen bond probability was used as a guideline for predicting conformational preferences of the photoisomers. Binding of these inhibitors has been rationalized by docking studies with the R1 unit. Significant differences in binding of the photoisomers were observed. For the shorter peptidomimetics, stronger binding of the Z isomer might indicate hydrophobic interactions between the stilbene chromophore and the binding site.

    National Category
    Organic Chemistry Medicinal Chemistry
    Research subject
    Chemistry with specialization in Organic Chemistry; Medicinal Chemistry
    Identifiers
    urn:nbn:se:uu:diva-239491 (URN)10.1039/C4OB01926A (DOI)000350144600018 ()25580895 (PubMedID)
    Funder
    Swedish Research Council
    Available from: 2014-12-28 Created: 2014-12-28 Last updated: 2018-01-11Bibliographically approved
    2. Synthesis and characterization of photoswitchable stiff-stilbene based amino acid derivatives
    Open this publication in new window or tab >>Synthesis and characterization of photoswitchable stiff-stilbene based amino acid derivatives
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Synthetic routes towards the Boc-protected amino acids 1 and 2 incorporating the stiff stilbene chromophore via the corresponding indanone carboxylic acids have been devised. Crucial steps are a reductive McMurry coupling of the indanone carboxylic acids, yielding stiff stilbene dicarboxylic acid esters. Hydrolysis to the monoester and conversion to the azides, followed by a Curtius rearrangement afforded the Boc-protected amino acid ester 1.

    Keywords
    Peptidomimetics
    National Category
    Organic Chemistry
    Research subject
    Chemistry with specialization in Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-267829 (URN)
    Funder
    Swedish Research Council, 621-2012-3379
    Available from: 2015-11-27 Created: 2015-11-27 Last updated: 2016-01-13
    3. Photoswitchable peptidomimetics with a stiff-stilbene chromophore for inhibition of Mycobacterium tuberculosis RNR
    Open this publication in new window or tab >>Photoswitchable peptidomimetics with a stiff-stilbene chromophore for inhibition of Mycobacterium tuberculosis RNR
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Peptidomimetics incorporating two amino acids 1 and 2 with a stiff stilbene chromophore have been screened by a computational study and compared to a previously investigated analog 3 with stilbene chromophore. The effect of E-Z isomerization of the chromophores on the conformational properties of the petidomimetics was assessed via the frequency of hydrogen bonding between the two peptide strands attached to either side of the chromophore. Substantial differences between the three amino acids were thus indicated, in line with the anticipated effect of chromophore rigidity variation.

    Keywords
    Peptidomimetics, conformational analysis
    National Category
    Organic Chemistry
    Research subject
    Chemistry with specialization in Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-267830 (URN)
    Funder
    Swedish Research Council, 621-2012-3379
    Available from: 2015-11-27 Created: 2015-11-27 Last updated: 2016-01-13
    4. Synthesis and Properties of Bis-Porphyrin Molecular Tweezers: Effects of Spacer Flexibility on Binding and Supramolecular Chirogenesis
    Open this publication in new window or tab >>Synthesis and Properties of Bis-Porphyrin Molecular Tweezers: Effects of Spacer Flexibility on Binding and Supramolecular Chirogenesis
    Show others...
    2016 (English)In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 21, no 1Article in journal (Refereed) Published
    Abstract [en]

    Abstract: Ditopic binding of various dinitrogen compounds to three bisporphyrin molecular tweezers with spacers of varying conformational rigidity, incorporating the planar ene-diyne (1), the helical stiff stilbene (2), or the semirigid glycoluril motif fused to  the porphyrins (3) are compared. Binding constants Ka = 10^4 to 10^6 M^-1 reveal subtle  differences between these tweezers, that are discussed in terms of porphyrin dislocation  modes. Exciton coupled circular dichroism (ECCD) of complexes with chiral dinitrogen  guests provides experimental evidence for the conformational properties of the tweezers. The results are further supported and rationalized by conformational analysis.

    Keywords
    Bisporphyrin tweezers, metalloporphyrins, porphyrinoids, host-guest chemistry, supramolecular chemistry, chirogenesis, chirality transfer, exciton coupled circular dichroism, conformational analysis
    National Category
    Organic Chemistry Engineering and Technology
    Research subject
    Chemistry with specialization in Organic Chemistry; Engineering Science with specialization in Nanotechnology and Functional Materials
    Identifiers
    urn:nbn:se:uu:diva-267826 (URN)10.3390/molecules21010016 (DOI)000369485600001 ()
    Funder
    Swedish Research Council, 621-2012-3379Swedish Research Council, 621-2011-4423
    Available from: 2015-11-27 Created: 2015-11-27 Last updated: 2017-12-01Bibliographically approved
    5. Photomodulable bis-porphyrin molecular tweezers as dynamic host systems for diamine guests
    Open this publication in new window or tab >>Photomodulable bis-porphyrin molecular tweezers as dynamic host systems for diamine guests
    Show others...
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Bisporphyrin molecular tweezers with an enediyne (1) or a stiff stilbene (2) photoswitchable spacer are proposed as systems for modulation of bitopic binding to diamine guests via E/Z photoisomerization. The photoisomerization has been monitored by UV-Vis and 1H NMR spectroscopy and occurs without side reactions such as Bergman cyclization. Possible applications are rationalized in terms of competitive binding involving monoamine/diamine mixtures, and are supported by conformational analysis of the envisioned host-guest complexes. Binding dynamics for conformationally flexible guests show significantly different performance of aliphatic 1,w-diamine guests with varying N-N distance.

    Keywords
    Bisporphyrin tweezers, supramolecular chemistry, photochemistry
    National Category
    Organic Chemistry
    Research subject
    Chemistry with specialization in Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-267833 (URN)
    Funder
    Swedish Research Council, 621-2012-3379
    Available from: 2015-11-27 Created: 2015-11-27 Last updated: 2016-01-13
  • 7.
    Blom, Magnus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Huang, Hao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Photoswitchable peptidomimetics with a stiff-stilbene chromophore for inhibition of Mycobacterium tuberculosis RNRManuscript (preprint) (Other academic)
    Abstract [en]

    Peptidomimetics incorporating two amino acids 1 and 2 with a stiff stilbene chromophore have been screened by a computational study and compared to a previously investigated analog 3 with stilbene chromophore. The effect of E-Z isomerization of the chromophores on the conformational properties of the petidomimetics was assessed via the frequency of hydrogen bonding between the two peptide strands attached to either side of the chromophore. Substantial differences between the three amino acids were thus indicated, in line with the anticipated effect of chromophore rigidity variation.

  • 8.
    Blom, Magnus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Huang, Hao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Synthesis and characterization of photoswitchable stiff-stilbene based amino acid derivativesManuscript (preprint) (Other academic)
    Abstract [en]

    Synthetic routes towards the Boc-protected amino acids 1 and 2 incorporating the stiff stilbene chromophore via the corresponding indanone carboxylic acids have been devised. Crucial steps are a reductive McMurry coupling of the indanone carboxylic acids, yielding stiff stilbene dicarboxylic acid esters. Hydrolysis to the monoester and conversion to the azides, followed by a Curtius rearrangement afforded the Boc-protected amino acid ester 1.

  • 9.
    Blom, Magnus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Norrehed, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Andersson, Claes-Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Huang, Hao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Light, Mark E.
    Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, U.K.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Synthesis and Properties of Bis-Porphyrin Molecular Tweezers: Effects of Spacer Flexibility on Binding and Supramolecular Chirogenesis2016In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 21, no 1Article in journal (Refereed)
    Abstract [en]

    Abstract: Ditopic binding of various dinitrogen compounds to three bisporphyrin molecular tweezers with spacers of varying conformational rigidity, incorporating the planar ene-diyne (1), the helical stiff stilbene (2), or the semirigid glycoluril motif fused to  the porphyrins (3) are compared. Binding constants Ka = 10^4 to 10^6 M^-1 reveal subtle  differences between these tweezers, that are discussed in terms of porphyrin dislocation  modes. Exciton coupled circular dichroism (ECCD) of complexes with chiral dinitrogen  guests provides experimental evidence for the conformational properties of the tweezers. The results are further supported and rationalized by conformational analysis.

  • 10.
    Blom, Magnus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Olsson, Sandra
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Norrehed, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Andersson, Claes-Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Photomodulable bis-porphyrin molecular tweezers as dynamic host systems for diamine guestsManuscript (preprint) (Other academic)
    Abstract [en]

    Bisporphyrin molecular tweezers with an enediyne (1) or a stiff stilbene (2) photoswitchable spacer are proposed as systems for modulation of bitopic binding to diamine guests via E/Z photoisomerization. The photoisomerization has been monitored by UV-Vis and 1H NMR spectroscopy and occurs without side reactions such as Bergman cyclization. Possible applications are rationalized in terms of competitive binding involving monoamine/diamine mixtures, and are supported by conformational analysis of the envisioned host-guest complexes. Binding dynamics for conformationally flexible guests show significantly different performance of aliphatic 1,w-diamine guests with varying N-N distance.

  • 11.
    Cadu, Alban
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Iridium Catalysed Asymmetric Hydrogenation of Pyridines2013Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis presents the hydrogenation of substituted pyridines using N,P-ligated iridium catalystsin homogeneous media. These iridium catalysts were developed within this research group in thepast decade. This method of hydrogenation is highly stereoselective, and in several cases good to excellent ees were obtained.The hydrogenation of substituted pyridines was studied: by screening for the catalyst giving thehighest conversion and ee, by optimising the reaction conditions and by attempting to improve existingcatalysts. New substrates were synthesised for this process, in particular alkyl substituted Nprotectedpyridines. Their reduction provided chiral piperidines, which could be used as chiralbuilding blocks once deprotected.

    List of papers
    1. Iridium-Catalyzed Asymmetric Hydrogenation of Substituted Pyridines
    Open this publication in new window or tab >>Iridium-Catalyzed Asymmetric Hydrogenation of Substituted Pyridines
    2013 (English)In: Asian Journal of Organic Chemistry, ISSN 2193-5807, Vol. 2, no 12, p. 1061-1065Article in journal (Refereed) Published
    Abstract [en]

    Asymmetric hydrogenation of ortho-substituted pyridines catalyzed by N,P-ligated iridium is demonstrated. To facilitate this reaction, the aromaticity of the pyridines was weakened by forming N-iminopyridium ylides. The reactions give very high conversions, and after a single recrystallization, excellent ee of up to 98 % was obtained. This method lends itself to the synthesis of chiral piperidine building blocks.

    Keywords
    hydrogenation, iridium, N-iminopyridium ylides, pyridines, selective catalysis
    National Category
    Organic Chemistry Inorganic Chemistry
    Research subject
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-212412 (URN)10.1002/ajoc.201300160 (DOI)000328218000008 ()
    Available from: 2013-12-10 Created: 2013-12-10 Last updated: 2017-01-25Bibliographically approved
  • 12.
    Cadu, Alban
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Noble Metal Catalysed Reductions and Rearrangements2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The focus of this thesis has been organometallic catalysis applied to compounds containing heteroatoms which are usually poisonous to metal catalysts, by channelling their innate reactivity advantageously. The studies described in this thesis concentrate, in the first part, on iridium catalysed asymmetric hydrogenation (papers I and II) and in the second part, on gold catalysed internal rearrangements (papers III and IV). In each case, two classes of compounds are studied: pyridinium salts or sulphurous compounds. The asymmetric hydrogenation of pyridinium compounds was performed with 2% loading of N,P-ligated Ir catalyst with I2 additive (paper I) to achieve moderate to good enantiomeric excess (up to 98%). In paper II, olefinic sulphones were hydrogenated with an efficient 0.5% catalytic loading. In most cases full conversion was obtained and with good to excellent ees (up to 99%). The products of these reductions are chiral compounds, which could constitute further chemical building blocks. Palladium and gold were used sequentially in paper III, in order to perform a “Click” thiol-yne reaction followed by a semi-Pinacol rearrangement, leading to isolated yields of up to 98%. In paper IV The gold catalysed rearrangement of alkyl-pyridinium diynes was conducted, with a number of substrates providing >90% NMR yield. A highly selective hydrogenation was performed with a heterogeneous palladium catalyst to yield single diastereomer products. This methodology consists of up to three steps, with two catalysts in one pot.

    List of papers
    1. Iridium-Catalyzed Asymmetric Hydrogenation of Substituted Pyridines
    Open this publication in new window or tab >>Iridium-Catalyzed Asymmetric Hydrogenation of Substituted Pyridines
    2013 (English)In: Asian Journal of Organic Chemistry, ISSN 2193-5807, Vol. 2, no 12, p. 1061-1065Article in journal (Refereed) Published
    Abstract [en]

    Asymmetric hydrogenation of ortho-substituted pyridines catalyzed by N,P-ligated iridium is demonstrated. To facilitate this reaction, the aromaticity of the pyridines was weakened by forming N-iminopyridium ylides. The reactions give very high conversions, and after a single recrystallization, excellent ee of up to 98 % was obtained. This method lends itself to the synthesis of chiral piperidine building blocks.

    Keywords
    hydrogenation, iridium, N-iminopyridium ylides, pyridines, selective catalysis
    National Category
    Organic Chemistry Inorganic Chemistry
    Research subject
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-212412 (URN)10.1002/ajoc.201300160 (DOI)000328218000008 ()
    Available from: 2013-12-10 Created: 2013-12-10 Last updated: 2017-01-25Bibliographically approved
    2. An Enantioselective Approach to the Preparation of Chiral Sulfones by Ir-Catalyzed Asymmetric Hydrogenation
    Open this publication in new window or tab >>An Enantioselective Approach to the Preparation of Chiral Sulfones by Ir-Catalyzed Asymmetric Hydrogenation
    Show others...
    2014 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 136, no 47, p. 16557-16562Article in journal (Refereed) Published
    Abstract [en]

    Several chiral sulfonyl compounds were prepared using the iridium catalyzed asymmetric hydrogenation reaction. Vinylic, allylic and homoallylic sulfone substitutions were investigated, and high enantioselectivity is maintained regardless of the location of the olefin with respect to the sulfone. Impressive stereoselectivity was obtained for dialkyl substitutions, which typically are challenging substrates in the hydrogenation. As expected, the more bulky Z-substrates were hydrogenated slower than the corresponding E isomers, and in slightly lower enantioselectivity.

    Place, publisher, year, edition, pages
    American Chemical Society (ACS), 2014
    National Category
    Organic Chemistry
    Research subject
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-236862 (URN)10.1021/ja5079877 (DOI)000345720500016 ()25300238 (PubMedID)
    Available from: 2014-11-24 Created: 2014-11-24 Last updated: 2017-12-05Bibliographically approved
    3. One-Pot Synthesis of Keto Thioethers by Palladium/Gold-Catalyzed Click and Pinacol Reactions
    Open this publication in new window or tab >>One-Pot Synthesis of Keto Thioethers by Palladium/Gold-Catalyzed Click and Pinacol Reactions
    Show others...
    2014 (English)In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 16, no 21, p. 5556-5559Article in journal (Refereed) Published
    Abstract [en]

    An atom-efficient synthesis of keto thioethers was devised via tandem gold/palladium catalysis. The reaction proceeds through a regioselective thiol attack at the β-position of the alcohol, followed by an alkyl, aryl, or benzyl 1,2-shift. Both acyclic and cyclic systems were studied, in the latter case leading to the ring expansion of cyclic substrates.

    Place, publisher, year, edition, pages
    American Chemical Society (ACS), 2014
    Keywords
    Gold, Palladium, thioether, catalysis, synthesis
    National Category
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-236857 (URN)10.1021/ol502553p (DOI)000344635200013 ()25325145 (PubMedID)
    Available from: 2014-11-24 Created: 2014-11-24 Last updated: 2017-12-05Bibliographically approved
    4. Dual Gold (I) Catalysed Cyclisation of Dialkynyl Pyridinium salts
    Open this publication in new window or tab >>Dual Gold (I) Catalysed Cyclisation of Dialkynyl Pyridinium salts
    Show others...
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Novel dialkynyl pyridines were synthesised and protected as alkyl salts for dual gold (I) catalysed cycloisomerisation. Different alkyl groups and counter ions were screened for the salts, with benzyl and PF6- providing the best results. The cyclisation led to NMR yields of >95% being obtained for a number of substrates. Step-wise hydrogenation of products could be carried out in one-pot by Pd/C, with selective reduction of the double bonds, followed by deprotection of the Bn group.

    Keywords
    chemistry
    National Category
    Organic Chemistry
    Research subject
    Chemistry with specialization in Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-272369 (URN)
    Available from: 2016-01-13 Created: 2016-01-13 Last updated: 2016-02-12Bibliographically approved
  • 13.
    Cadu, Alban
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Andersson, Pher G.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Development of iridium-catalyzed asymmetric hydrogenation: New catalysts, new substrate scope2012In: Journal of Organometallic Chemistry, ISSN 0022-328X, E-ISSN 1872-8561, Vol. 714, p. 3-11Article, review/survey (Refereed)
    Abstract [en]

    A review. The asym. hydrogenation of olefins is a tremendously powerful tool used to synthesize chiral mols. The field was pioneered using rhodium- and ruthenium- based catalysts; however, catalysts based on both of these metals suffer from limitations, such as the need for directing substituents near or even adjacent to the olefin. Iridium-based catalysts do not suffer from this flaw and can thus hydrogenate a wide variety of olefins, including some tetra substituted ones. It is also possible for iridium-based catalysts to hydrogenate hetero-π bonds such as those found in heteroarom. rings. This review summarizes the contributions made to this field by the authors in the past few years. [on SciFinder(R)]

  • 14.
    Cadu, Alban
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Andersson, Pher G
    Iridium catalysis: Application of asymmetric reductive hydrogenation2013In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 42, no 40, p. 14345-14356Article in journal (Refereed)
    Abstract [en]

    Iridium, despite being one of the least abundant transition metals, has found several uses. N,P-ligated iridium catalysts are used to perform many highly selective reactions. These methodologies have been developed extensively over the past 15 years. More recently, the application of iridium N,P catalysts in asymmetric hydrogenation has been a focus of research to find novel applications and to expand on their current synthetic utility. The aim of this perspective is to highlight the advances made by the Andersson group.

  • 15.
    Cadu, Alban
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Upadhyay, Puspesh K.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry.
    Andersson, Pher G.
    Stockholm University.
    Iridium-Catalyzed Asymmetric Hydrogenation of Substituted Pyridines2013In: Asian Journal of Organic Chemistry, ISSN 2193-5807, Vol. 2, no 12, p. 1061-1065Article in journal (Refereed)
    Abstract [en]

    Asymmetric hydrogenation of ortho-substituted pyridines catalyzed by N,P-ligated iridium is demonstrated. To facilitate this reaction, the aromaticity of the pyridines was weakened by forming N-iminopyridium ylides. The reactions give very high conversions, and after a single recrystallization, excellent ee of up to 98 % was obtained. This method lends itself to the synthesis of chiral piperidine building blocks.

  • 16.
    Cadu, Alban
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Watile, Rahul
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Biswas, Srijit
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Sjöberg, Per J
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Samec, Joseph
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    One-Pot Synthesis of Keto Thioethers by Palladium/Gold-Catalyzed Click and Pinacol Reactions2014In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 16, no 21, p. 5556-5559Article in journal (Refereed)
    Abstract [en]

    An atom-efficient synthesis of keto thioethers was devised via tandem gold/palladium catalysis. The reaction proceeds through a regioselective thiol attack at the β-position of the alcohol, followed by an alkyl, aryl, or benzyl 1,2-shift. Both acyclic and cyclic systems were studied, in the latter case leading to the ring expansion of cyclic substrates.

  • 17.
    Dinér, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Superacid-Promoted Ionization of Alkanes Without Carbonium Ion Formation: A Density Functional Theory Study2012In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 116, no 40, p. 9979-9984Article in journal (Refereed)
    Abstract [en]

    The carbonium ion has been suggested to be the intermediate in superacid-promoted reactions (SbF5-HF) such as hydrogen-deuterium exchange and in the electrophilic C-H cleavage into hydrogen and the carbenium ion. In this study, the superacid-promoted C-H cleavage into hydrogen and the carbenium ion was studied using density functional theory (B3LYP and M062X) and ab initio methods (MP2 and CCSD). The calculations suggest that the superacid-promoted C-H cleavage proceeds via a concerted transition state leading to hydrogen (H-2) and the carbenium ion without the formation of the elusive carbonium ion. The reactivity for the superacid promoted C-H cleavage decreases upon going from isobutane (tertiary) > propane (secondary) > isobutane (primary) > propane (primary) > ethane >> methane.

  • 18.
    Galkin, Maxim
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Palladium-catalyzed lignin valorization: Towards a lignin-based biorefinery2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The work described in this thesis focuses on the cleavage of the β-O-4′ bond, which is the most abundant interunit linkage in the lignin polymer.

    In the first part, three methods based on palladium catalysis have been developed and their applicability has been verified using lignin model compounds. A transfer hydrogenolysis of the β-O-4′ bond using formic acid as a mild hydrogen donor together with a base. An aerobic oxidation of the benzylic alcohol motif in the β-O-4′ linkage to generate a key intermediate in the cleavage reaction was performed. A redox neutral cleavage of the β-O-4′ bond was accomplished in which no stoichiometric reducing or oxidizing agents were added.

    In the second part of the thesis, a mechanistic study is presented. The corresponding ketone from a dehydrogenation reaction of the benzylic alcohol motif was identified to be the key intermediate. This ketone and its enol tautomer was found to be responsible for the β-O-4′ bond cleavage reaction under the employed reaction conditions.

    In the final part of this thesis, the methodologies have been applied to native lignin. The depolymerization reaction was combined with organosolv pulping. This approach was successful, and together with cellulose and hemicellulose, propenyl aryls were generated in excellent yields directly from wood. In this transformation, the lignin derived molecules have been reduced by an endogenous hydrogen donor from the wood.

    List of papers
    1. Mild Heterogeneous Palladium-Catalyzed Cleavage of beta-O-4 '-Ether Linkages of Lignin Model Compounds and Native Lignin in Air
    Open this publication in new window or tab >>Mild Heterogeneous Palladium-Catalyzed Cleavage of beta-O-4 '-Ether Linkages of Lignin Model Compounds and Native Lignin in Air
    Show others...
    2014 (English)In: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 6, no 1, p. 179-184Article in journal (Refereed) Published
    Abstract [en]

    A mild and robust heterogeneous palladium-catalyzed CO bond cleavage of 2-aryloxy-1-arylethanols using formic acid as reducing agent in air was developed. The cleaved products were isolated in 92-98% yield; and by slightly varying the reaction conditions, a ketone, an alcohol, or an alkane can be generated in near-quantitative yield. This reaction is applicable to cleaving the -O-4-ether bond found in lignin polymers of different origin. The reaction was performed on a lignin polymer model to generate either the monomeric aryl ketone or alkane in a quantitative yield. Moderate depolymerization was achieved with native lignin at similar reaction conditions. Mechanistic studies under kinetic control indicate that an initial palladium-catalyzed dehydrogenation of the alcohol is followed by insertion of palladium to an enol equivalent. A palladium-formato complex reductively cleaves the palladium-enolate complex to generate the ketone.

    Keywords
    heterogeneous catalysis, cleavage reactions, green chemistry, palladium, polymers, lignin
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-220309 (URN)10.1002/cctc.201300540 (DOI)000330636800023 ()
    Note

    De två första författarna delar första författarskapet.

    Available from: 2014-03-17 Created: 2014-03-12 Last updated: 2017-12-05Bibliographically approved
    2. Selective Aerobic Benzylic Alcohol Oxidation of Lignin Model Compounds: Route to Aryl Ketones
    Open this publication in new window or tab >>Selective Aerobic Benzylic Alcohol Oxidation of Lignin Model Compounds: Route to Aryl Ketones
    2015 (English)In: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 7, no 3, p. 401-404Article in journal (Refereed) Published
    Abstract [en]

    A mild and chemoselective oxidation of the -alcohol in -O-4-ethanoaryl and -O-4-glycerolaryl ethers has been developed. The benzylic alcohols were selectively dehydrogenated to the corresponding ketones in 60-93% yield. A one-pot selective route to aryl ethyl ketones was performed. The catalytic system comprises recyclable heterogeneous palladium, mild reaction conditions, green solvents, and oxygen in air as oxidant. Catalytic amounts of a coordinating polyol were found pivotal for an efficient aerobic oxidation.

    Keywords
    biomass valorization, heterogeneous catalysis, lignin, oxidation, palladium
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-246820 (URN)10.1002/cctc.201402825 (DOI)000349147100005 ()
    Available from: 2015-03-11 Created: 2015-03-10 Last updated: 2017-12-04Bibliographically approved
    3. Mild and Robust Redox-Neutral Pd/C-Catalyzed Lignol -O-4 Bond Cleavage Through a Low-Energy-Barrier Pathway
    Open this publication in new window or tab >>Mild and Robust Redox-Neutral Pd/C-Catalyzed Lignol -O-4 Bond Cleavage Through a Low-Energy-Barrier Pathway
    2015 (English)In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 8, no 13, p. 2187-2192Article in journal (Refereed) Published
    Abstract [en]

    A Pd/C catalyzed redox neutral CO bond cleavage of 2-aryloxy-1-arylethanols has been developed. The reactions are carried out at 80 degrees C, in air, using a green solvent system to yield the aryl ketones in near quantitative yields. Addition of catalytic amounts of a hydrogen source to the reaction mixture activates the catalyst to proceed through a low energy barrier pathway. Initial studies support a transfer hydrogenolysis reaction mechanism that proceeds through an initial dehydrogenation followed by an enol adsorption to Pd/C and a reductive CO bond cleavage.

    Keywords
    heterogeneous catalysis, lignin, palladium, reaction mechanisms, transfer hydrogenolysis
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-259649 (URN)10.1002/cssc.201500117 (DOI)000357619000004 ()25925736 (PubMedID)
    Funder
    Swedish Energy Agency
    Available from: 2015-08-20 Created: 2015-08-10 Last updated: 2017-12-04Bibliographically approved
    4. Selective Route to 2-Propenyl Aryls Directly from Wood by a Tandem Organosolv and Palladium-Catalysed Transfer Hydrogenolysis
    Open this publication in new window or tab >>Selective Route to 2-Propenyl Aryls Directly from Wood by a Tandem Organosolv and Palladium-Catalysed Transfer Hydrogenolysis
    2014 (English)In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 7, no 8, p. 2154-2158Article in journal (Refereed) Published
    Abstract [en]

    A tandem organosolv pulping and Pd-catalysed transfer hydrogenolysis depolymerisation and deoxygenation has been developed. The tandem process generated 2-methoxy-4-(prop-1-enyl)phenol in 23 % yield (92 % theoretical monomer yield) starting from pine wood and 2,6-dimethoxy-4-(prop-1-enyl)phenol in 49 % yield (92 % theoretical monomer yield) starting from birch wood. Only endogenous hydrogen from wood was consumed, and the reaction was performed using green solvents.

    Keywords
    Biomass, Lignin Green, Chemistry, Palladium, catalysis
    National Category
    Organic Chemistry
    Research subject
    Chemistry with specialization in Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-226637 (URN)10.1002/cssc.201402017 (DOI)000340519500016 ()
    Funder
    Swedish Energy Agency
    Available from: 2014-06-18 Created: 2014-06-18 Last updated: 2017-12-05Bibliographically approved
  • 19.
    Galkin, Maxim
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Samec, Joseph
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Selective Route to 2-Propenyl Aryls Directly from Wood by a Tandem Organosolv and Palladium-Catalysed Transfer Hydrogenolysis2014In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 7, no 8, p. 2154-2158Article in journal (Refereed)
    Abstract [en]

    A tandem organosolv pulping and Pd-catalysed transfer hydrogenolysis depolymerisation and deoxygenation has been developed. The tandem process generated 2-methoxy-4-(prop-1-enyl)phenol in 23 % yield (92 % theoretical monomer yield) starting from pine wood and 2,6-dimethoxy-4-(prop-1-enyl)phenol in 49 % yield (92 % theoretical monomer yield) starting from birch wood. Only endogenous hydrogen from wood was consumed, and the reaction was performed using green solvents.

  • 20.
    Galkin, Maxim V.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Sawadjoon, Supaporn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Rohde, Volker
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Dawange, Monali
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Samec, Joseph S. M.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Mild Heterogeneous Palladium-Catalyzed Cleavage of beta-O-4 '-Ether Linkages of Lignin Model Compounds and Native Lignin in Air2014In: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 6, no 1, p. 179-184Article in journal (Refereed)
    Abstract [en]

    A mild and robust heterogeneous palladium-catalyzed CO bond cleavage of 2-aryloxy-1-arylethanols using formic acid as reducing agent in air was developed. The cleaved products were isolated in 92-98% yield; and by slightly varying the reaction conditions, a ketone, an alcohol, or an alkane can be generated in near-quantitative yield. This reaction is applicable to cleaving the -O-4-ether bond found in lignin polymers of different origin. The reaction was performed on a lignin polymer model to generate either the monomeric aryl ketone or alkane in a quantitative yield. Moderate depolymerization was achieved with native lignin at similar reaction conditions. Mechanistic studies under kinetic control indicate that an initial palladium-catalyzed dehydrogenation of the alcohol is followed by insertion of palladium to an enol equivalent. A palladium-formato complex reductively cleaves the palladium-enolate complex to generate the ketone.

  • 21.
    Gustafsson, Tomas
    et al.
    Karolinska Inst, Div Biochem, Dept Med Biochem & Biophys, Scheeles Vag 2, SE-17177 Stockholm, Sweden.; Umea Univ, Sunderby Res Unit, Dept Clin Microbiol, Clin Bacteriol, Umea, Sweden.
    Osman, Harer
    Karolinska Inst, Div Biochem, Dept Med Biochem & Biophys, Scheeles Vag 2, SE-17177 Stockholm, Sweden.
    Werngren, Jim
    Publ Hlth Agcy Sweden, Dept Microbiol, Solna, Sweden.
    Hoffner, Sven
    Publ Hlth Agcy Sweden, Dept Microbiol, Solna, Sweden.
    Engman, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Holmgren, Arne
    Karolinska Inst, Div Biochem, Dept Med Biochem & Biophys, Scheeles Vag 2, SE-17177 Stockholm, Sweden.
    Ebselen and analogs as inhibitors of Bacillus anthracis thioredoxin reductase and bactericidal antibacterials targeting Bacillus species, Staphylococcus aureus and Mycobacterium tuberculosis2016In: Biochimica et Biophysica Acta - General Subjects, ISSN 0304-4165, E-ISSN 1872-8006, Vol. 1860, no 6, p. 1265-1271Article in journal (Refereed)
    Abstract [en]

    Background: Bacillus anthracis is the causative agent of anthrax, a disease associated with a very high mortality rate in its invasive forms.

    Methods: We studied a number of ebselen analogs as inhibitors of B. anthracis thioredoxin reductase and their antibacterial activity on Bacillus subtilis, Staphylococcus aureus, Bacillus cereus and Mycobacterium tuberculosis.

    Results: The most potent compounds in the series gave IC50 values down to 70 nM for the pure enzyme and minimal inhibitory concentrations (MICs) down to 0.4 mu M (0.12 mu g/ml) for B. subtilis,1.5 mu M (0.64 mu g/ml) for S. aureus, 2 mu M (0.86 mu g/ml) for B. cereus and 10 mu g/ml for M. tuberculosis. Minimal bactericidal concentrations (MBCs) were found at 1-1.5 times the MIC, indicating a general, class-dependent, bactericidal mode of action. The combined bacteriological and enzymological data were used to construct a preliminary structure-activity-relationship for the benzoisoselenazol class of compounds. When S. aureus and B. subtilis were exposed to ebselen, we were unable to isolate resistant mutants on both solid and in liquid medium suggesting a high resistance barrier.

    Conclusions: These results suggest that ebselen and analogs thereof could be developed into a novel antibiotic class, useful for the treatment of infections caused by B. anthracis, S. aureus, M. tuberculosis and other clinically important bacteria. Furthermore, the high barrier against resistance development is encouraging for further drug development.

    General significance: We have characterized the thioredoxin system from B. anthracis as a novel drug target and ebselen and analogs thereof as a potential new class of antibiotics targeting several important human pathogens.

  • 22.
    Hao, Huang
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Karlsson, Christoffer
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Quinone Based Polypyrroles for Energy Storage Materials2015Conference paper (Refereed)
  • 23.
    Huang, Hao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Karlsson, Christoffer
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Hydroquinone–pyrrole dyads with varied linkers2016In: Beilstein Journal of Organic Chemistry, ISSN 2195-951X, E-ISSN 1860-5397, Vol. 12, p. 89-96Article in journal (Refereed)
    Abstract [en]

    A series of pyrroles functionalized in the 3-position with p-dimethoxybenzene via various linkers (CH2, CH2CH2, CH=CH, C≡C) has been synthesized. Their electronic properties have been deduced from 1H NMR, 13C NMR, and UV–vis spectra to detect possible interactions between the two aromatic subunits. The extent of conjugation between the subunits is largely controlled by the nature of the linker, with the largest conjugation found with the trans-ethene linker and the weakest with the aliphatic linkers. DFT calculations revealed substantial changes in the HOMO–LUMO gap that correlated with the extent of conjugation found experimentally. The results of this work are expected to open up for use of the investigated compounds as components of redox-active materials in sustainable, organic electrical energy storage devices.

  • 24.
    Huang, Xiao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Yang, Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Synthesis and Redox Properties of Thiophene Terephthalate Building Blocks for Low-Potential Conducting Redox Polymers2015In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 119, no 49, p. 27247-27254Article in journal (Refereed)
    Abstract [en]

    Terephthalate-substituted thiophene derivatives are promising redox-active components for anode materials in lithium-ion batteries. In this study, we present the synthesis of substituted 2-(thiophen-3-yl)terephthalate derivatives (TTDs) as suitable monomers for thiophene-based conducting redox polymers, along with their characterization by electrochemical and spectroscopic techniques. Density functional theory (DFT) calculations, utilizing the universal solvation model based on solute electron density (SMD), were used to predict both the first and the second reduction potentials of these TTDs. The computational results showed good agreement with the experimental data in nonaqueous acetonitrile solvent, with mean absolute errors of 30 and 40 mV for the first and second reduction steps, respectively. Time-dependent (TD) DFT calculations on TTDs indicated terephthalate local transitions at both 200 and 240 nm and charge-transfer transitions above 300 nm by examination of the involved molecular orbitals.

  • 25.
    Huang, Xiao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Yang, Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    The n-type polymers pending with terephthalate group attempt for organic anode material2014Conference paper (Refereed)
  • 26.
    Huang, Xiao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Yang, Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    The n-type polymers with terephthalate group attempt for organic anode material2014Conference paper (Refereed)
  • 27.
    Huang, Xiao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Yang, Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Synthesis and Redox Properties of Thiophene-Terephthalate Building Blocks for Low Potential Conducting Redox Polymers2015In: 66th Annual Meeting of the International Society of Electrochemistry Proceeding., 2015Conference paper (Refereed)
  • 28.
    Karlsson, Christoffer
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Blom, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Johansson, Miranda
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Jansson, Anna M.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Scifo, Enzo
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Karlén, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Govender, Thavendran
    Catalysis and Peptide Research Unit, University of KwaZulu Natal, South Africa.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Phototriggerable peptidomimetics for the inhibition of Mycobacterium turberculosis ribonucleotide reductase by targeting protein-protein binding2015In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 13, no 9, p. 2612-2621Article in journal (Refereed)
    Abstract [en]

    Incorporation of an artificial amino acid 2 with a stilbene chromophore into peptidomimetics with three to nine amino acids yields phototriggerable candidates for inhibition of the binding between the R1 and R2 subunits of the M. tuberculosis ribonucleotide reductase (RNR). Interstrand hydrogen bond probability was used as a guideline for predicting conformational preferences of the photoisomers. Binding of these inhibitors has been rationalized by docking studies with the R1 unit. Significant differences in binding of the photoisomers were observed. For the shorter peptidomimetics, stronger binding of the Z isomer might indicate hydrophobic interactions between the stilbene chromophore and the binding site.

  • 29.
    Karlsson, Christoffer
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Investigation of the Redox Chemistry of Isoindole-4,7-diones2013In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 117, no 2, p. 894-901Article in journal (Refereed)
    Abstract [en]

    Quinone derivatives have been proposed as active components in lithium ion battery (LIB) electrode materials. In this work the electrochemistry of a series of substituted isoindole-4,7-diones (IIDs) was investigated. Three new IID derivatives were synthesized and characterized by various electrochemical and spectroscopic techniques. Polymerization was attempted to achieve a conducting polymer with redox active quinone side groups, which would be advantageous in a LIB application. A combination of in situ spectroelectrochemical measurements and density functional theory (DFT) calculations was used to investigate the proton coupled redox reactions of the IIDs. Results from a previous computational study of the IIDs were compared with experimental data here, and the agreement was very good. The energy of the spectroscopic transitions in the UV and in the visible region showed different correlation with redox potential and quinone substituent in the series of IIDs. This behavior was rationalized by examination of the involved molecular orbitals. The results indicated that the properties of the quinone unit, such as the redox potential, could be selectively varied by substitution.

  • 30.
    Karlsson, Christoffer
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Huang, Hao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Olsson, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Kinetics of conducting polymers with side chain quinone units2013Conference paper (Refereed)
    Abstract [en]

    Quinones have been suggested as active material in organic lithium ion battery (LIB) cathodes. They are expected to have higher specific capacities and to be cheaper and more environmentally friendly than the inorganic lithium intercalation compounds used in LIBs today. However, quinone compounds suggested for this purpose often suffer from slow kinetics and low cyclability due to dissolution. In this work, conducting polymers containing pending quinone moieties were synthesized. Immobilizing the redox active quinone units on a conducting polymer matrix decreases both resistance and solubility, which improves the speed and the cyclability of the system, while maintaining a high specific capacity. The two-electron redox reaction of the quinone units in these polymers yields a theoretical capacity of ~300 mAh/g. The polymers were studied electrochemically and spectroscopically to elucidate the kinetics of the polymer charging and the redox cycling of the quinone units.

  • 31.
    Karlsson, Christoffer
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Huang, Hao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Ion- and Electron Transport in Pyrrole/Quinone Conducting Redox Polymers Investigated by In Situ Conductivity Methods2015In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 179, p. 336-342Article in journal (Refereed)
    Abstract [en]

    Polypyrrole functionalized with redox active pendant groups constitutes a so called conducting redox polymer, and functions both as a conducting polymer and as a redox polymer. The electrochemical response reveals capacitive charging of the conducting backbone as well as redox cycling of the pendant groups. While the backbone provides an electrically conducting matrix for fast electron transport through the material, the pendant groups offer a large charge storage capacity, much greater than that of polypyrrole itself. We have investigated such polypyrrole-hydroquinone conducting redox polymers, with focus on their in situ conductivity during electrochemical cycling, in order to understand the charge transport mechanisms in this type of system. The most notable feature is that oxidation of the pendant groups leads to a large decrease in the polymer conductivity. The causes of this phenomenon are discussed, as well as the rate limitations of fast redox cycling of the polymer, which are investigated through a combination of bipotentiostat cyclic voltammetry and potential steps of polymer films on interdigitated array electrodes.

  • 32.
    Karlsson, Christoffer
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Huang, Hao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Charge transport in pyrrole/quinone conducting redox polymers2014Conference paper (Refereed)
  • 33.
    Karlsson, Christoffer
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Huang, Hao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Impact of Linker in Polypyrrole/Quinone Conducting Redox Polymers2015In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 5, no 15, p. 11309-11316Article in journal (Refereed)
    Abstract [en]

    Organic conducting redox polymers are being investigated as the active component for secondary battery applications, as they have the potential to solve two of the main problems with small molecule-based organic electrodes for electrical energy storage, viz dissolution of the active compound in the electrolyte, and slow charge transport through the material. Herein we report the synthesis of a series of conducting redox polymers based on polypyrrole with hydroquinone pendant groups that are attached to the backbone via different linkers, and we investigate the impact of the linker on the interaction between the backbone and the pendant groups. For the directly linked polymer, oxidation of the pendant groups leads to a decrease of bipolaron absorbance, as well as a decrease in mass of the polymer film, both of which are reversible. The origin of these effects is discussed in light of the influence of the linker unit, electrolyte polarity, and electrolyte salt. For the longest linkers in the series, no interaction was observed, which was deemed the most beneficial situation for energy storage applications, as the energy storage capacity of the pendant groups can be utilized without disturbing the conductivity of the polymer backbone.

  • 34.
    Karlsson, Christoffer
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Huang, Hao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Polymer–Pendant Interactions in Poly(pyrrol-3-ylhydroquinone): A Solution for the Use of Conducting Polymers at Stable Conditions2013In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 117, no 45, p. 23558-23567Article in journal (Refereed)
    Abstract [en]

    While various organic molecules have been suggested as environmentally friendly alternatives to inorganic electrode materials for lithium ion batteries, most of them suffer from slow kinetics as well as capacity fading due to dissolution. Herein we present the synthesis of poly(pyrrol-3-ylhydroquinone) (PPyQ), a polypyrrole (PPy) derivative with pending hydroquinone groups, for investigation of the use of a conducting polymer to immobilize redox active quinone units. This strategy eliminates dissolution of the active material while also increasing the conductivity. The quinone pending groups in PPyQ cycle reversibly in the potential region where the polymer backbone is conducting and chemically stable. In situ spectroelectrochemistry on PPyQ films reveals UV/vis transitions inherent to PPy, as well as quinone centered transitions, allowing detailed investigation of the interplay between the polymer doping process and the quinone redox conversion. Intriguingly, it is found that the charging of the PPy backbone halts during the redox reaction of the quinone pending groups. This opens up for the possibility of using PPy at low and constant doping levels while utilizing the charge storage capacity of the quinone pending groups when creating electric energy storage materials based on sustainable and renewable components.

  • 35.
    Karlsson, Christoffer
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Huang, Hao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Probing Polymer-Pendant Interactions in the Conducting Redox Polymer Poly(pyrrol-3-ylhydroquinone)2014In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 118, no 41, p. 23499-23508Article in journal (Refereed)
    Abstract [en]

    Conducting polymers with redox active pendant groups show properties typical of both conducting polymers (i.e., capacitive charging and intrinsic conductivity) and redox polymers (i.e., electrochemical surface response at the formal potential of the pendant groups). The two components can also exert significant interaction on each other during their separate electrochemical reactions. In poly(pyrrol-3-ylhydroquinone), a polypyrrole derivative functionalized with hydroquinone units, the redox conversion of the pendant groups has a large impact on the polymer backbone. This interaction is manifested by a loss of bipolaron states during the hydroquinone oxidation, leading to a decreasing p-doping level with increasing potential, something which, to the best of our knowledge, has never been observed for a conducting polymer. Another effect is a contraction of the polymer film, and subsequent mass loss due to solvent expulsion upon hydroquinone oxidation, which counteracts the normal swelling of polypyrrole with increased potential. The conducting redox polymer under investigation has been synthesized via two routes, leading to different fractions of subunits bearing redox active hydroquinone groups. While the redox potentials are unaffected by the synthesis route, the backbone/pendant group interaction varies notably depending on the degree of quinone functionalization. This type of polymers could find use in, e.g., organic energy storage materials, since the polymer backbone both increases the electronic conductivity and prevents dissolution of the active material, as well as in actuator application, due to polymer contraction over the relatively narrow potential region where the pendant group redox chemistry occurs.

  • 36.
    Karlsson, Christoffer
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Huang, Hao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Quinone Pendant Group Kinetics in Poly(pyrrol-3-ylhydroquinone)2014In: Journal of Electroanalytical Chemistry, ISSN 0022-0728, E-ISSN 1873-2569, Vol. 735, p. 95-98Article in journal (Refereed)
    Abstract [en]

    Herein, we investigate the kinetics of the redox processes occurring in acidic aqueous electrolyte in electropolymerized poly(pyrrol-3-ylhydroquinone), which has been proposed for electrical energy storage applications. The redox conversion of the pendant groups is found to be limited by the quinone redox kinetics in thin films, rather than by the conduction through the polypyrrole backbone. Rate constants for the elementary steps involved in this 2e, 2H+ process are reported. As the films are made thicker, a gradual transition to a diffusion limited reaction is observed. The origin of the diffusion process, as well as the elementary reaction steps limiting the pendant group redox conversion is analyzed using DFT computations. The fact that the electron transport through the thin film conducting polymer backbone is not limiting the quinone reaction kinetics should allow for design of battery electrodes with high rate capabilities based on the studied material.

  • 37.
    Kirchhain, Arno
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Yu, Wenbin
    Engman, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Organochalcogen stabilizers efficiently protect model polyolefins exposed to chlorinated media2015In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 118, p. 82-87Article in journal (Refereed)
    Abstract [en]

    The small amounts of chlorine dioxide that are routinely supplemented to drinking water as a disinfectant also cause a degradation of the polyolefin pipes that are used for distribution of the water. Commonly used phenolic antioxidants can extend the service life of the polymer but the expected lifetime is still much shorter than desired (50 years) due to depletion of the antioxidant in the surface zone exposed to the aqueous solution. In search for better stabilizers for the pipes, we have tested an organotellurium compound, 4-(N,N-dimethylamino)phenyl 3-phenoxypropyl telluride (1), as well as its corresponding selenium and sulphur analogues and a series of organotellurium compounds where the electron density at the heteroatom was varied. Stabilizers were dissolved in squalane, which is a liquid hydrocarbon that could serve as a model for a polyolefin. The oxidation induction time (OIT), determined after exposure of the squalane solution to an aqueous solution of 10 ppm of chlorine dioxide for various times was determined by DSC to indicate the loss of antioxidant protection. Whereas Irganox 1010 was only effective as a stabilizer for a few hours, many of the organochalcogen compounds were considerably more resistant (>91 h for compound 1) towards chlorine dioxide.

    Thermogravimetric analyses of antioxidants indicated insignificant decomposition below 200 °C and increasing stability for the lighter chalcogen compounds (telluride < selenide < sulfide). Among organotelluriums, stability increases with increasing electron density at the heteroatom. Oxidation potentials of stabilizers as determined by cyclic voltammetry correlated fairly well with their protective effect in squalane (OIT-values). We therefore hypothesize that these compounds act primarily as electron donors towards peroxyl radicals. As determined by 125Te NMR-spectroscopy, organotellurium compound 1 in the presence of an excess of chlorine dioxide failed to produce an oxidation product. This may be the clue to its long-lasting protective effect in the squalane-assay.

  • 38.
    Li, Jia-Qi
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Studies of Hydrogenations and Isomerizations of Olefins and Alkylations of Amines Using Iridium Catalysts2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis describes three types of reactions that were carried out using iridium catalysts.

    The first type is the iridium-catalyzed asymmetric hydrogenation of olefins. In paper I, the preparation of a new type of bicyclic thiazole-phosphine based iridium complex was described. The new catalysts have displayed high activity and enantioselectivity in the asymmetric hydrogenation of unfunctionalized olefins. Papers II and III focus on the expansion of the substrate scope for the iridium catalyzed asymmetric hydrogenation in which a number of heterocyclic olefins were evaluated. In paper IV, the enantioselective asymmetric hydrogenation of α, β-unsaturated esters was described. The chiral products bearing tertiary stereogenic centers obtained by hydrogenation have great synthetic value and have been used in the synthesis of pharmaceuticals as well as in the total synthesis of natural products.

    The second type is the asymmetric isomerization of allylic alcohols. In paper V, both cis and trans primary allylic alcohols were isomerized to the corresponding β-chiral aldehydes in high enantioselectivities by an N,P-chelating iridium complex.

    The third type is the selective mono-N-alkylation of amines with alcohols. In paper VI, a phosphine/NHC based iridium catalyst was synthesized and applied in the alkylation of amines. It is the first time that this type of transformation is carried out at room temperature.

    List of papers
    1. Bicyclic phosphine-thiazole ligands for the asymmetric hydrogenation of olefins
    Open this publication in new window or tab >>Bicyclic phosphine-thiazole ligands for the asymmetric hydrogenation of olefins
    2010 (English)In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 21, no 11-12, p. 1328-1333Article in journal (Refereed) Published
    Abstract [en]

    New bicyclic thiazole-based chiral N,P-chelating ligands were developed. High activities and enantioselectivities were achieved in the iridium-catalyzed asymmetric hydrogenation of olefins with the new ligands.

    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-135190 (URN)10.1016/j.tetasy.2010.03.023 (DOI)000281095300002 ()
    Available from: 2010-12-06 Created: 2010-12-06 Last updated: 2017-12-11Bibliographically approved
    2. Highly Flexible Synthesis of Chiral Azacycles via Iridium-Catalyzed Hydrogenation
    Open this publication in new window or tab >>Highly Flexible Synthesis of Chiral Azacycles via Iridium-Catalyzed Hydrogenation
    Show others...
    2010 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 132, no 26, p. 8880-8881Article in journal (Refereed) Published
    Abstract [en]

    A range of saturated chiral azacycles has been prepared in high yield and with high selectivity from simple starting materials. A modular approach with ring-closing metathesis as a key step was used to produce a number of five-, six-, and seven-membered cyclic alkenes. Asymmetric hydrogenation catalyzed by N,P-ligated iridium complexes gave saturated azacycles in high optical purity. This methodology was demonstrated in the synthesis of a pharmaceutical precursor.

    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-135809 (URN)10.1021/ja103901e (DOI)000279561200033 ()20557052 (PubMedID)
    Available from: 2010-12-09 Created: 2010-12-08 Last updated: 2017-12-11Bibliographically approved
    3. Chiral Hetero- and Carbocyclic Compounds from the Asymmetric Hydrogenation of Cyclic Alkenes
    Open this publication in new window or tab >>Chiral Hetero- and Carbocyclic Compounds from the Asymmetric Hydrogenation of Cyclic Alkenes
    Show others...
    2012 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, no 21, p. 6507-6513Article in journal (Refereed) Published
    Abstract [en]

    Several types of chiral hetero- and carbocyclic compounds have been synthesized by using the asymmetric hydrogenation of cyclic alkenes. N,P-Ligated iridium catalysts reduced six-membered cyclic alkenes with various substituents and heterofunctionality in good to excellent enantioselectivity, whereas the reduction of five-membered cyclic alkenes was generally less selective, giving modest enantiomeric excesses. The stereoselectivity of the hydrogenation depended more strongly on the substrate structure for the five- rather than the six-membered cyclic alkenes. The major enantiomer formed in the reduction of six-membered alkenes could be predicted from a selectivity model and isomeric alkenes had complementary enantioselectivity, giving opposite optical isomers upon hydrogenation. The utility of the reaction was demonstrated by using it as a key step in the preparation of chiral 1,3-cis-cyclohexane carboxylates.

    Keywords
    asymmetric synthesis, heterocyclic compounds, homogeneous catalysis, hydrogenation, iridium
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-175620 (URN)10.1002/chem.201104073 (DOI)000304045000016 ()
    Available from: 2012-06-12 Created: 2012-06-11 Last updated: 2017-12-07Bibliographically approved
    4. Highly Enantioselective Asymmetric Isomerization of Primary Allylic Alcohols with an Iridium-N,P Complex
    Open this publication in new window or tab >>Highly Enantioselective Asymmetric Isomerization of Primary Allylic Alcohols with an Iridium-N,P Complex
    2011 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 17, no 40, p. 11143-11145Article in journal (Refereed) Published
    Keywords
    aldehydes, allylic alcohols, asymmetric catalysis, iridium, isomerization, N, P ligands
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-164577 (URN)10.1002/chem.201101524 (DOI)000297013100011 ()
    Available from: 2011-12-21 Created: 2011-12-21 Last updated: 2017-12-08Bibliographically approved
    5. Highly Enantioselective Iridium-Catalyzed Hydrogenation of α,β-Unsaturated Esters
    Open this publication in new window or tab >>Highly Enantioselective Iridium-Catalyzed Hydrogenation of α,β-Unsaturated Esters
    2012 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, no 34, p. 10609-10616Article in journal (Refereed) Published
    Abstract [en]

    α,β-Unsaturated esters have been employed as substrates in iridium-catalyzed asymmetric hydrogenation. Full conversions and good to excellent enantioselectivities (up to 99 % ee) were obtained for a broad range of substrates with both aromatic- and aliphatic substituents on the prochiral carbon. The hydrogenated products are highly useful as building blocks in the synthesis of a variety of natural products and pharmaceuticals.

    National Category
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-182641 (URN)10.1002/chem.201200907 (DOI)000307387300020 ()22807347 (PubMedID)
    Available from: 2012-10-14 Created: 2012-10-14 Last updated: 2017-12-07Bibliographically approved
    6. Room Temperature and Solvent-Free Iridium-Catalyzed  Alkylation of Amines with Alcohols
    Open this publication in new window or tab >>Room Temperature and Solvent-Free Iridium-Catalyzed  Alkylation of Amines with Alcohols
    (English)Manuscript (preprint) (Other academic)
    National Category
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-182645 (URN)
    Available from: 2012-10-16 Created: 2012-10-14 Last updated: 2012-11-12
  • 39.
    Li, Jia-Qi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Andersson, Pher
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Room Temperature and Solvent-Free Iridium-Catalyzed  Alkylation of Amines with AlcoholsManuscript (preprint) (Other academic)
  • 40.
    Li, Jia-Qi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Xu, Quan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Andersson, Pher
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Highly Enantioselective Iridium-Catalyzed Hydrogenation of α,β-Unsaturated Esters2012In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, no 34, p. 10609-10616Article in journal (Refereed)
    Abstract [en]

    α,β-Unsaturated esters have been employed as substrates in iridium-catalyzed asymmetric hydrogenation. Full conversions and good to excellent enantioselectivities (up to 99 % ee) were obtained for a broad range of substrates with both aromatic- and aliphatic substituents on the prochiral carbon. The hydrogenated products are highly useful as building blocks in the synthesis of a variety of natural products and pharmaceuticals.

  • 41.
    Lu, Jun
    et al.
    Karolinska Institutet.
    Vlamis-Gardikas, Alexios
    Karolinska Institutet.
    Kandasamy, Karuppasamy
    Karolinska Institutet.
    Zhao, Rong
    Karolinska Institutet.
    Gustafsson, Tomas
    Karolinska Institutet.
    Engstrand, Lars
    Karolinska Institutet.
    Hoffner, Sven
    Karolinska Institutet.
    Engman, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Holmgren, Arne
    Karolinska Institutet.
    Inhibition of Bacterial Thioredoxin Reductase: An Antibiotic Mechanism Targetting Bacteria Lacking Glutathione2013In: The FASEB Journal, ISSN 0892-6638, E-ISSN 1530-6860, Vol. 27, no 4, p. 1394-1403Article in journal (Refereed)
    Abstract [en]

     Increasing antibiotic resistance makes the identification of new antibacterial principles an urgent task. The thioredoxin system including thioredoxinreductase (TrxR), thioredoxin (Trx), and NADPH plays critical roles in cellular DNA synthesis and defense against oxidative stress. Notably, TrxR is very different in structure and mechanism in mammals and bacteria. Ebselen [2-phenyl-1,2 benzisoselenazol-3(2H)-one], a well-known antioxidant and a substrate for mammalian TrxR and Trx, is rapidly bacteriocidal for methicillin-resistant Staphylococcus aureus by an unknown mechanism. We have discovered that ebselen is a competitive inhibitor of Escherichia coli TrxR with a K-i of 0.52 +/- 0.13 mu M, through reaction with the active site dithiol of the enzyme. Bacteria lacking glutathione (GSH) and glutaredoxin, in which TrxR and Trx are essential for DNA synthesis, were particularly sensitive to ebselen. In growth-inhibited E. coli strains, Trx1 and Trx2 were oxidized, demonstrating that electron transfer via thioredoxin was blocked. Ebselen and its sulfur analog ebsulfur were bactericidal for GSH-negative pathogens. Ebsulfur inhibited a clinically isolated Helicobacter pylori strain with a minimum inhibitory concentration value as low as 0.39 mu g/ml. These results demonstrate that bacterial Trx and TrxR are viable antibacterial drug targets using benzisoselenazol and benzisothiazol derivates.-Lu, J., Vlamis-Gardikas, A., Kandasamy, K., Zhao, R., Gustafsson, T. N., Engstrand, L., Hoffner, S., Engman, L., Holmgren, A. Inhibition of bacterial thioredoxin reductase: an antibiotic mechanism targeting bacteria lacking glutathione. 

  • 42.
    Mesas Sánchez, Laura
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Organocatalytic Acylation for the Kinetic Resolution of Secondary Aryl Alcohols: Synthetic Applications and Mechanistic Studies2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The research described in this thesis focuses on the catalytic acylative kinetic resolution (KR) of aromatic secondary alcohols, using a planar-chiral 4-(dimethylamino)pyridine (DMAP) organocatalyst.

    In the first part of this thesis, the substrate scope of the above mentioned process was expanded to aromatic secondary alcohols that contain an extra functional group in the alkyl moiety, such as 1,2-azido alcohols, 2-hydroxy-2-aryl-ethylphosphonates and 2-hydroxy-2-aryl esters. Thus, the preparation of highly functionalized compounds in their enantiomerically pure form with excellent enantiomeric excess (up to 99% ee) was achieved. Furthermore, the synthetic applicability of this methodology was illustrated through the synthesis of two high value compounds, (R)-Pronethalol and (S)-3-hydroxy-N-methyl-3-phenylpropanamide, which is an immediate precursor of bioactive molecules such as (S)-Fluoxetine.

    The second part of this thesis deals with the mechanistic study of the acylative KR catalyzed by the planar-chiral DMAP derivative. Reaction Progress Kinetic Analysis methodology was used in the investigation of the reaction mechanism, probing that no notable product inhibition or decomposition of the catalyst occurs in the studied system. The reaction rate showed fractional order dependence on the concentration of both reactants. Furthermore, NMR spectroscopy was utilized to study the equilibrium between the different catalyst states, which explains the measured kinetics of the reaction.

    List of papers
    1. Non-enzymatic kinetic resolution of 1,2-azidoalcohols using a planar-chiral DMAP derivative catalyst
    Open this publication in new window or tab >>Non-enzymatic kinetic resolution of 1,2-azidoalcohols using a planar-chiral DMAP derivative catalyst
    2013 (English)In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 69, no 2, p. 753-757Article in journal (Refereed) Published
    Abstract [en]

    Optically pure 1,2-azidoalcohols are widely used as precursors for other high value organic products. A non-enzymatic kinetic resolution procedure for the stereoselective synthesis of chiral 1,2-azidoalcohols from the readily available racemic counterparts has been developed, employing a planar-chiral DMAP derivative catalyst. Following this procedure, a range of aromatic 1,2-azidoalcohols was obtained in good selectivities (up to S=45) and high enantiomeric excess (up to 99% ee).

    Keywords
    Non-enzymatic kinetic resolution, 1, 2-Azidoalcohols, Planar-chiral DMAP derivative catalyst, Ferrocenyl catalyst
    National Category
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-189450 (URN)10.1016/j.tet.2012.10.077 (DOI)000314371800045 ()
    Available from: 2013-01-02 Created: 2013-01-02 Last updated: 2017-12-06Bibliographically approved
    2. Kinetic resolution of 2-hydroxy-2-aryl-ethylphosphonates by a non-enzymatic acylation catalyst
    Open this publication in new window or tab >>Kinetic resolution of 2-hydroxy-2-aryl-ethylphosphonates by a non-enzymatic acylation catalyst
    2014 (English)In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 70, no 24, p. 3807-3811Article in journal (Refereed) Published
    Abstract [en]

    Optically pure hydroxyphosphonates are widely used as derivatizable compounds that can be incorporated into a variety of synthetic strategies for the preparation of other high value organic products. A non-enzymatic kinetic resolution procedure to obtain chiral 2-hydroxy-2-arylethylphosphonates from the easily available racemic counterparts is described. A range of 2-hydroxy-2-arylethylphosphonates was efficiently resolved employing a planar-chiral DMAP derived catalyst with good selectivities (up to S=68). The chiral hydroxyphosphonates were isolated in good yields and high enantiomeric excess (>94% ee).

    Keywords
    Non-enzymatic kinetic resolution, 2-Hydroxy-2-arylethylphosphonates, Planar chiral DMAP derivative catalyst
    National Category
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-227994 (URN)10.1016/j.tet.2014.03.102 (DOI)000336710200010 ()
    Available from: 2014-07-04 Created: 2014-07-02 Last updated: 2017-12-05Bibliographically approved
    3. Access to optically pure β-hydroxy esters via non-enzymatic kinetic resolution by a planar-chiral DMAP catalyst
    Open this publication in new window or tab >>Access to optically pure β-hydroxy esters via non-enzymatic kinetic resolution by a planar-chiral DMAP catalyst
    2014 (English)In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 19, no 9, p. 14273-14291Article in journal (Refereed) Published
    Abstract [en]

    The development of new approaches to obtain optically pure β-hydroxy esters is an important area in synthetic organic chemistry since they are precursors of other high value compounds. Herein, the kinetic resolution of racemic β-hydroxy esters using a planar-chiral DMAP derivative catalyst is presented. Following this procedure, a range of aromatic β-hydroxy esters was obtained in excellent selectivities (up to = 107) and high enantiomeric excess (up to 99% ee). Furthermore, the utility of the present method was demonstrated in the synthesis of (S)-3-hydroxy-N-methyl-3-phenylpropanamide, a key intermediate for bioactive molecules such as fluoxetine, tomoxetine or nisoxetine, in its enantiomerically pure form.

    Keywords
    non-enzymatic kinetic resolution, β-hydroxy esters, planar-chiral DMAP catalyst, ferrocenyl catalyst
    National Category
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-224444 (URN)10.3390/molecules190914273 (DOI)000343093100085 ()25215586 (PubMedID)
    Note

    Alba E. DiazIvarez and Laura Mesas-Sanchez contributed equally to this work.

    Available from: 2014-10-08 Created: 2014-05-12 Last updated: 2017-12-05Bibliographically approved
    4. A Mechanistic Investigation of the Kinetic Resolution of Secondary Aromatic Alcohols Using a Ferrocene-Based Planar Chiral 4-(Dimethylamino)pyridine Catalyst
    Open this publication in new window or tab >>A Mechanistic Investigation of the Kinetic Resolution of Secondary Aromatic Alcohols Using a Ferrocene-Based Planar Chiral 4-(Dimethylamino)pyridine Catalyst
    2015 (English)In: CHEMISTRY-A EUROPEAN JOURNAL, ISSN 0947-6539, Vol. 21, no 14, p. 5623-5631Article in journal (Refereed) Published
    Abstract [en]

    A detailed kinetic analysis for the acetylation of 1-phenylethanol with acetic anhydride catalyzed by the planar chiral DMAP catalyst (–)-1 is presented. The study include a computational investigation of the potential energy surface including the rate-limiting and stereoselective transitionstates at the DFT level of theory. The kinetic study suggests that the reaction proceeds with first order in catalyst and in 1-phenylethanol, while the acetic anhydride shows a fractional order. The fractional order is racionalized based on an equilibrium between the free and the acetylated catalyst.

    Keywords
    Reaction progress kinetic analysis, DFT calculation
    National Category
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-233714 (URN)10.1002/chem.201405793 (DOI)000352504500041 ()25677932 (PubMedID)
    Available from: 2014-10-09 Created: 2014-10-08 Last updated: 2015-05-12Bibliographically approved
  • 43.
    Mesas-Sánchez, Laura
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Dinér, Peter
    KTH Royal Institute of Technology.
    A Mechanistic Investigation of the Kinetic Resolution of Secondary Aromatic Alcohols Using a Ferrocene-Based Planar Chiral 4-(Dimethylamino)pyridine Catalyst2015In: CHEMISTRY-A EUROPEAN JOURNAL, ISSN 0947-6539, Vol. 21, no 14, p. 5623-5631Article in journal (Refereed)
    Abstract [en]

    A detailed kinetic analysis for the acetylation of 1-phenylethanol with acetic anhydride catalyzed by the planar chiral DMAP catalyst (–)-1 is presented. The study include a computational investigation of the potential energy surface including the rate-limiting and stereoselective transitionstates at the DFT level of theory. The kinetic study suggests that the reaction proceeds with first order in catalyst and in 1-phenylethanol, while the acetic anhydride shows a fractional order. The fractional order is racionalized based on an equilibrium between the free and the acetylated catalyst.

  • 44. Mirzaei, Anvar
    et al.
    Biswas, Srijit
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Samec, Joseph
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Iron(III)-Catalyzed Nucleophilic Substitution of the Hydroxy Group in Benzoin by Alcohols2012In: Synthesis (Stuttgart), ISSN 0039-7881, E-ISSN 1437-210X, Vol. 44, no 8, p. 1213-1218Article in journal (Refereed)
    Abstract [en]

    The etherification reaction between benzoin derivatives and alcohols catalyzed by iron(III) proceeds in moderate to good yields. Other metal complexes showed either low reactivity or low chemoselectivity where oxidation of benzoin to benzil was a competing reaction. The iron source operated as a catalyst where 5 mol% of iron(III) generate the 2-alkoxy-1,2-diphenylethan-1-one in 50% yield. With an optimum of 25 mol% of catalyst, the desired ether was obtained in 85% yield. The etherification of benzoin and an alcohol proceed to generate the desired product in polar solvents such as 1,2-dichloroethane, whereas less polar solvents promote the competing oxidation to generate the benzil; polar coordinating solvents such as tetrahydrofuran inhibited the reaction. The efficiency of the reaction is found to be dependent on nucleophile where an optimum of 30 equivalents of alcohol was observed. With electron-­donating substituents on the aromatic ring, the etherification was followed by oxidation to generate the benzil. Moderate yields of etherification product were obtained by monitoring the reaction progress with electron-rich substrates and quenching the reaction after two hours.

  • 45.
    Nachtigall, Olaf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Lomoth, Reiner
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Dahlstrand, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Lundstedt, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Webb, Matthew J
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Pyrene–Azobenzene Dyads and Their Photochemistry2014In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, Vol. 2014, no 5, p. 966-972Article in journal (Refereed)
    Abstract [en]

    The facile synthesis of three new folding azobenzene-pyrene systems 13, connected together by a serendipitously obtained and unpredicted ester linkage, is reported. Additional characterization of the photochemistry of these systems revealed variations in azobenzene photoisomerization (trans-cis and cis-trans) and quenching of pyrene fluorescence, as a result of intra-excitation energy transfer from the pyrene chromophore to an azobenzene. Through the use of aryl substituent electronic effects to tune the absorption properties of the azobenzene relative to the pyrene, we show that efficient photo-switching can be achieved when the trans-azobenzene absorbance band is well separated from that of the pyrene (compound 1), whereas overlap of the corresponding absorbance bands in the cases of 2 and 3 significantly compromises trans-cis isomerization by enhancing cis-trans interconversion.

  • 46.
    Norrehed, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Modulation of Molecular Properties: Host–Guest Interactions for Structural Analysis and Chemical Reactions2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis concerns the construction, use and modulation of various host–guest systems, from small bispidines for binding of inorganic ions to bisporphyrin clips for supramolecular systems.

    Small flexible molecules undergo fast conformational movements when in solution. These conformational movements generate time-averaged population-weighted chemical shifts, coupling constants and NOEs when analysed by NMR spectroscopy. A bisporphyrin clip was designed to be used as a host for restriction of conformational movements of small flexible molecules by ditopic metal-ligand binding. Based on conformational analysis in combination with NMR analysis of molecular flexibility in solution (NAMFIS), the relative stereochemistry of flexible alditol-derived diamines containing three or four consecutive stereocentres could be determined.

    To further explore the idea of conformational deconvolution via host–guest binding, two flexible molecular tweezers with photoswitchable moieties were developed. Upon photoswitching cis/trans isomerisation facilitates the opening and closing of these bisporphyrin hosts. A guest molecule could then be exposed to a “catch and stretch” or “catch and release” effect. Preliminary studies have shown that photoisomerisation of the constructed systems is possible without photodecomposition and preliminary binding studies have been conducted.

    Controlled modulation of molecular conformations is of interest especially if the conformational steering activates a unit working as a nucleator in a larger structure or facilitates a reaction. The protonation-triggered modulation of bispidine conformations has been investigated. In addition to previously reported conformations we have observed that upon diprotonation a bispidine derivative can be driven into the unusual boat-boat conformation.

    Finally, the unexpected formation of persistent organic radicals with a cyclophane motif from the reaction of N,N´-diphenyl-1-5-diazacyclooctane and AgBF4 is described. Interestingly, these diradicals exhibit features such as intramolecular π-stacking without lateral displacement and also intramolecular spin pairing.

     

    List of papers
    1. Conformational restriction of flexible molecules in solution by a semirigid bis-porphyrin molecular tweezer
    Open this publication in new window or tab >>Conformational restriction of flexible molecules in solution by a semirigid bis-porphyrin molecular tweezer
    Show others...
    2013 (English)In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 69, no 34, p. 7131-7138Article in journal (Refereed) Published
    Abstract [en]

    A semirigid bis-porphyrin molecular clip with a glycoluril backbone has been synthesized. The clip provides an adaptable molecular cavity for binding of diamines. Binding constants for diamines of 104–107 M−1 are orders of magnitude higher than those for monoamines of 103 M−1, indicating a preference to bidentate binding. NMR studies confirmed that binding of bidentate guests occurs inside the clip. Short- and medium-size acyclic molecular guests are locked into a single, extended conformation, and also guests with longer flexible chains exhibit considerably less conformational mobility than when free in solution. The size of the cavity adapts to the guest size, as indicated by modelling studies and self diffusion constants of the complexes.

    Keywords
    Conformational analysis, NMR spectroscopy, Hosteguest systems, Supramolecular chemistry, Porphyrinoids
    National Category
    Natural Sciences Organic Chemistry
    Research subject
    Chemistry with specialization in Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-206036 (URN)10.1016/j.tet.2013.06.013 (DOI)000322098000027 ()
    Funder
    Swedish Research Council
    Available from: 2013-08-26 Created: 2013-08-26 Last updated: 2017-12-06Bibliographically approved
    2. Improved stereochemical analysis of conformationally flexible diamines by binding to a bisporphyrin molecular clip
    Open this publication in new window or tab >>Improved stereochemical analysis of conformationally flexible diamines by binding to a bisporphyrin molecular clip
    2013 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 19, no 43, p. 14631-14638Article in journal (Refereed) Published
    Abstract [en]

    The relative stereochemistry of acyclic diamines with several stereogenic centers has been analyzed by NMR spectroscopy in combination with conformational deconvolution. Binding to a bisporphyrin molecular clip improves the stereochemical assignment significantly. The diamines were synthesized from inexpensive sugar alcohols, and their stable hydrochlorides were quantitatively converted into free bases by treatment with ion-exchange resin.

    Keywords
    configuration determination, conformational analysis, host–guest systems, N ligands, NMR spectroscopy
    National Category
    Natural Sciences Organic Chemistry
    Research subject
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-206040 (URN)10.1002/chem.201300533 (DOI)000330288400025 ()
    Funder
    Swedish Research Council
    Available from: 2013-08-26 Created: 2013-08-26 Last updated: 2017-12-06Bibliographically approved
    3. Photomodulable bis-porphyrin molecular tweezers for conformational studies of diamine guests
    Open this publication in new window or tab >>Photomodulable bis-porphyrin molecular tweezers for conformational studies of diamine guests
    Show others...
    (English)Manuscript (preprint) (Other academic)
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-206039 (URN)
    Available from: 2013-08-26 Created: 2013-08-26 Last updated: 2014-01-23
    4. Protonation-triggered Conformational Modulation of an N,N´‑Dialkylbispidine: First observation of the elusive boat-boat conformer
    Open this publication in new window or tab >>Protonation-triggered Conformational Modulation of an N,N´‑Dialkylbispidine: First observation of the elusive boat-boat conformer
    2013 (English)In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 11, p. 6292-6299Article in journal (Refereed) Published
    Abstract [en]

    Modulation of the solution conformations of N,N′-bis(benzhydryl)bispidine has been achieved by protonation. Conformers have been characterized by NMR spectroscopy using nuclear Overhauser effects and residual dipolar couplings. In contrast to the preference for the chair–chair conformation for the free base and the monoprotonated species, the diprotonated bispidine is revealed to exist as a mixture of chair–boat and boat–boat conformers. While boat–boat conformers of bispidines have previously not been detected, they are here observed to constitute up to 70% of the bispidine population.

    National Category
    Natural Sciences Organic Chemistry
    Research subject
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-206042 (URN)10.1039/c3ob41122b (DOI)000324507100010 ()
    Funder
    Swedish Research Council
    Available from: 2013-08-26 Created: 2013-08-26 Last updated: 2017-12-06Bibliographically approved
    5. Synthesis of persistent organic dication diradicals incorporating a cyclophane motif with intramolecular pi-stacking
    Open this publication in new window or tab >>Synthesis of persistent organic dication diradicals incorporating a cyclophane motif with intramolecular pi-stacking
    Show others...
    (English)Article in journal (Other academic) Submitted
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-206043 (URN)
    Available from: 2013-08-26 Created: 2013-08-26 Last updated: 2014-01-23Bibliographically approved
  • 47.
    Norrehed, Sara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Erdélyi, Maté
    Light, Mark E.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Protonation-triggered Conformational Modulation of an N,N´‑Dialkylbispidine: First observation of the elusive boat-boat conformer2013In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 11, p. 6292-6299Article in journal (Refereed)
    Abstract [en]

    Modulation of the solution conformations of N,N′-bis(benzhydryl)bispidine has been achieved by protonation. Conformers have been characterized by NMR spectroscopy using nuclear Overhauser effects and residual dipolar couplings. In contrast to the preference for the chair–chair conformation for the free base and the monoprotonated species, the diprotonated bispidine is revealed to exist as a mixture of chair–boat and boat–boat conformers. While boat–boat conformers of bispidines have previously not been detected, they are here observed to constitute up to 70% of the bispidine population.

  • 48.
    Norrehed, Sara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Johansson, Henrik
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Improved stereochemical analysis of conformationally flexible diamines by binding to a bisporphyrin molecular clip2013In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 19, no 43, p. 14631-14638Article in journal (Refereed)
    Abstract [en]

    The relative stereochemistry of acyclic diamines with several stereogenic centers has been analyzed by NMR spectroscopy in combination with conformational deconvolution. Binding to a bisporphyrin molecular clip improves the stereochemical assignment significantly. The diamines were synthesized from inexpensive sugar alcohols, and their stable hydrochlorides were quantitatively converted into free bases by treatment with ion-exchange resin.

  • 49.
    Norrehed, Sara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Polavarapu, Prasad
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Yang, Wenzhi
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Conformational restriction of flexible molecules in solution by a semirigid bis-porphyrin molecular tweezer2013In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 69, no 34, p. 7131-7138Article in journal (Refereed)
    Abstract [en]

    A semirigid bis-porphyrin molecular clip with a glycoluril backbone has been synthesized. The clip provides an adaptable molecular cavity for binding of diamines. Binding constants for diamines of 104–107 M−1 are orders of magnitude higher than those for monoamines of 103 M−1, indicating a preference to bidentate binding. NMR studies confirmed that binding of bidentate guests occurs inside the clip. Short- and medium-size acyclic molecular guests are locked into a single, extended conformation, and also guests with longer flexible chains exhibit considerably less conformational mobility than when free in solution. The size of the cavity adapts to the guest size, as indicated by modelling studies and self diffusion constants of the complexes.

  • 50.
    Paptchikhine, Alexander
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Asymmetric Hydrogenations using N, P - Ligated Iridium Complexes2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The research described in this thesis focuses on the catalytic asymmetric hydrogenation of prochiral olefins using N, P – chelated iridium catalysts. This catalytic system is tolerant to a wide range of substrates and performs better than the well-known ruthenium- and rhodium-catalytic systems for substrates devoid of coordinating groups in proximity of the olefin. Low catalytic loadings (often <1 %) and the high atom efficiency of this reaction make it a synthetically useful method of chiral molecule synthesis. The primary aim of this thesis was to develop new catalysts that rapidly and efficiently hydrogenate a broad range of alkenes asymmetrically. Papers I and II describe the synthesis and evaluation of new, highly efficient, chiral N, P – ligated iridium complexes. These catalysts were obtained in relatively few steps, while leaving open possibilities to modify and fine-tune their structure. Their versatility is ideally suited to both industrial uses and to equip any catalyst box. Paper III deals with a common problem of defluorination of vinylic fluorides during the hydrogenation. The catalyst designed in that work performs well for several substrates giving very low defluorination rates making it a good starting point for further improvements to cover a broader scope of vinyl fluorides. The structures of the catalysts from papers I and III also offers an easy approach to attach the catalyst ligands to a solid support. Paper IV explores hydrogenation of vinyl boronates, which gives synthetically interesting borane compounds with high enantioselectivities. Taking into account the rich chemistry of organic boranes, these compounds are very important. Paper V deals with hydrogenation of diphenylvinylphosphine oxides and vinyl phosphonates, another important classes of substrates that give chiral phosphorous containing compounds of interest in many fields of chemistry: such as medicinal chemistry and organocatalysis. In papers VI and VII we explore the Birch reaction as a source of prochiral olefins. By combining asymmetric hydrogenation with it, we obtain a powerful method to create chiral compounds with excellent enantioselectivities that are next to impossible to make by other routes. The products of the asymmetric hydrogenation are further modified by other well-known transformation to create other induced stereogenic centres.

    List of papers
    1. Development of new thiazole-based iridium catalysts and their applications in the asymmetric hydrogenation of trisubstituted olefins
    Open this publication in new window or tab >>Development of new thiazole-based iridium catalysts and their applications in the asymmetric hydrogenation of trisubstituted olefins
    Show others...
    2008 (English)In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 6, p. 366-373Article in journal (Refereed) Published
    National Category
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-173458 (URN)
    Available from: 2012-04-24 Created: 2012-04-24 Last updated: 2017-12-07
    2. Bicyclic phosphine-thiazole ligands for the asymmetric hydrogenation of olefins
    Open this publication in new window or tab >>Bicyclic phosphine-thiazole ligands for the asymmetric hydrogenation of olefins
    2010 (English)In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 21, no 11-12, p. 1328-1333Article in journal (Refereed) Published
    Abstract [en]

    New bicyclic thiazole-based chiral N,P-chelating ligands were developed. High activities and enantioselectivities were achieved in the iridium-catalyzed asymmetric hydrogenation of olefins with the new ligands.

    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-135190 (URN)10.1016/j.tetasy.2010.03.023 (DOI)000281095300002 ()
    Available from: 2010-12-06 Created: 2010-12-06 Last updated: 2017-12-11Bibliographically approved
    3. Iridium-Catalyzed Asymmetric Hydrogenation of Fluorinated Olefins Using N,P-Ligands: A struggle with hydrogenolysis and selectivity
    Open this publication in new window or tab >>Iridium-Catalyzed Asymmetric Hydrogenation of Fluorinated Olefins Using N,P-Ligands: A struggle with hydrogenolysis and selectivity
    2007 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 129, no 15, p. 4536-4537Article in journal (Refereed) Published
    Abstract [en]

    To broaden the substrate scope of asymmetric iridium-catalyzed hydrogenation, fluorine-functionalized olefins were synthesized and hydrogenated with iridium complexes. Preliminary results showed high levels of fluorine elimination together with low selectivity. The loss of vinylic fluorine at first seemed difficult to handle, but further studies revealed that a catalyst with an azanorbornyl scaffold in the ligand gave more promising results. With this in mind, a new ligand was developed. This gave among the best results published to date for fluorine asymmetric hydrogenation, yielding high conversion and very high ee's with very little fluorine elimination. Further increasing the selectivity, the trials also revealed that tetrasubstituted fluorine-containing olefins can be hydrogenated with high ee's, despite that this class of compounds has usually shown low reactivity in this reaction type.

    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-97352 (URN)10.1021/ja0686763 (DOI)000245739700016 ()17375924 (PubMedID)
    Available from: 2008-05-13 Created: 2008-05-13 Last updated: 2017-12-14Bibliographically approved
    4. Iridium-catalyzed enantioselective hydrogenation of vinyl boronates
    Open this publication in new window or tab >>Iridium-catalyzed enantioselective hydrogenation of vinyl boronates
    2009 (English)In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, no 40, p. 5996-5998Article in journal (Refereed) Published
    Abstract [en]

    The first Ir-catalyzed asymmetric hydrogenations of vinyl boronates have been performed using low catalyst loadings (0.5 mol%) and pressure (as low as 1 bar). Good selectivities (76-98% ee) were obtained for a range of substrates.

    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-121862 (URN)10.1039/b912590f (DOI)000270542300008 ()19809622 (PubMedID)
    Available from: 2010-03-31 Created: 2010-03-31 Last updated: 2017-12-12Bibliographically approved
    5. Iridium-N,P-ligand-catalyzed enantioselective hydrogenation of diphenylvinylphosphine oxides and vinylphosphonates
    Open this publication in new window or tab >>Iridium-N,P-ligand-catalyzed enantioselective hydrogenation of diphenylvinylphosphine oxides and vinylphosphonates
    2009 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 131, no 23, p. 8285-8289Article in journal (Refereed) Published
    Abstract [en]

    Diphenylvinylphosphine oxides and di- and trisubstituted vinylphosphonates have been employed as substrates in iridium-catalyzed asymmetric hydrogenations. Complete conversions and excellent enantioselectivities (up to and above 99% ee) were observed for a range of substrates with both aromatic and aliphatic groups at the prochiral carbon. We have also hydrogenated electron-deficient carboxyethylvinylphosphonates with excellent stereoselectivity (up to and above 99% ee). The hydrogenated products of both classes of substrates are synthetically useful intermediates.

    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-121865 (URN)10.1021/ja901437t (DOI)000267623100057 ()19462955 (PubMedID)
    Available from: 2010-03-31 Created: 2010-03-31 Last updated: 2017-12-12Bibliographically approved
    6. Sequential Birch reaction and asymmetric Ir-catalyzed hydrogenation as a route to chiral building blocks
    Open this publication in new window or tab >>Sequential Birch reaction and asymmetric Ir-catalyzed hydrogenation as a route to chiral building blocks
    2011 (English)In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 47, no 13, p. 3989-3991Article in journal (Refereed) Published
    Abstract [en]

    A range of 1,2,4-trisubstituted cyclohexadienes obtained from the Birch reaction were hydrogenated asymmetrically to produce synthetically valuable chiral compounds in high enantio- and diastereoselectivity.

    National Category
    Biochemistry and Molecular Biology
    Identifiers
    urn:nbn:se:uu:diva-150770 (URN)10.1039/c0cc05619g (DOI)000288386600089 ()21327284 (PubMedID)
    Available from: 2011-04-06 Created: 2011-04-06 Last updated: 2017-12-11Bibliographically approved
    7. The Birch reaction as a source of substrates for asymmetric hydrogenation
    Open this publication in new window or tab >>The Birch reaction as a source of substrates for asymmetric hydrogenation
    (English)Manuscript (preprint) (Other academic)
    Keywords
    birch reaction, asymmetric hydrogenation, cyclohexanes, 1, 6-diketone
    National Category
    Organic Chemistry
    Research subject
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-173230 (URN)
    Available from: 2012-04-20 Created: 2012-04-20 Last updated: 2012-08-01
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