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  • 51.
    Paptchikhine, Alexander
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Peters, Byron
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Govender, Thavendran
    School of Chemistry, University of KwaZulu-Natal.
    Andersson, Pher
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    The Birch reaction as a source of substrates for asymmetric hydrogenationManuskript (preprint) (Annet vitenskapelig)
  • 52. Peters, Byron K.
    et al.
    Zhou, Taigang
    Rujirawanich, Janjira
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Cadu, Alban
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Singh, Thishana
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Rabten, Wangchuk
    Kerdphon, Suttichat
    Andersson, Pher G.
    An Enantioselective Approach to the Preparation of Chiral Sulfones by Ir-Catalyzed Asymmetric Hydrogenation2014Inngår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 136, nr 47, s. 16557-16562Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 53.
    Poon, Jia-Fei
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Alao, John Patrick
    Sunnerhagen, Per
    Dinér, Peter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Azastilbenes: a cut-off to p38 MAPK inhibitors2013Inngår i: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 11, nr 27, s. 4526-4536Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Inhibitors with vicinal 4-fluorophenyl/4-pyridine rings on a five- or six-membered heterocyclic ring are known to inhibit the p38 mitogen-activated protein kinase (MAPK), which is a potential target for rheumatoid arthritis and several different types of cancer. Several substituted azastilbene-based compounds with vicinal 4-fluorophenyl/4-pyridine rings were designed using computational docking, synthesized, and evaluated in a cell-free radiometric p38[small alpha] assay. The biochemical evaluation shows that the best inhibition (down to 110 nM) is achieved for azastilbene-based compounds having an isopropylamine substituent in the 2-position of the pyridine ring. The inhibition of p38 signaling in human breast cancer cells was observed for two of the compounds.

  • 54.
    Poon, Jia-fei
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Singh, Vijay P.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Biokemi.
    Engman, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    In Search of Catalytic Antioxidants-(Alkyltelluro)phenols, (Alkyltelluro)resorcinols, and Bis(alkyltelluro)phenols2013Inngår i: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 78, nr 12, s. 6008-6015Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The quenching of peroxyl radicals by ortho-(alkyltelluro)phenols occurs by a more complex mechanism than formal H-atom transfer. In an effort to improve on this concept, we have prepared (alkyltelluro)resorcinols and bis(alkyltelluro)phenols and evaluated their catalytic chain breaking and preventive antioxidative properties. The in situ formed trianion produced from 2-bromophenol and 3 equiv of tert-butyllithiutn was allowed to react with dialkyl ditellurides to provide ortho-(alkyltelluro)phenols in low yields. 2-Bromoresorcinols after treatment with 4 equiv of tert-butyllithium similarly afforded 2-(alkyltelluro)resorcinols. Bis(alkyltelluro)phenols were accessed by allowing the trianion produced from the reaction of 2,6-dibromophenol with 5 equiv of tert-butyllithium to react with dialkyl ditellurides. The novel phenolic compounds were found to inhibit azo-initiated peroxidation of linoleic acid much more efficiently than alpha-tocopherol in a two-phase peroxidation system containing excess N-acetylcysteine as a stoichiometric thiol reducing agent in the aqueous phase. Whereas most of the (alkyltelluro)phenols and resorcinols could inhibit peroxidation for only 89-228 min, some of the bis(alkyltelluro)phenols were more regenerable and offered protection for >410 min. The novel (alkyltelluro)phenols were also evaluated for their capacity to catalyze reduction of hydrogen peroxide in the presence of thiophenol (glutathione peroxidase-like activity). (Alkyltelluro)resorcinols 7a-c were the most efficient catalysts with activities circa 65 times higher than those recorded for diphenyl diselenide.

  • 55.
    Rydergren, Sara
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Chemical Modifications of Hyaluronan using DMTMM-Activated Amidation2013Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    An alternative approach to chemically modifying hyaluronan (HA) has been investigated. The triazine derivative 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium (DMTMM) has been used to activate carboxylic groups on HA, which react further to form stable amide bonds with primary and secondary amines. The reaction can either be used to couple monoamines to HA or to produce hydrogels by using diamines that form crosslinks between the HA chains. The reaction between HA and DMTMM has been investigated and optimized in regard to degree of substitution (DS). Analysis using SEC-LC-UV demonstrated that the reaction was successful in coupling benzylamine to HA with a DS of 40%. Gel formation was successful using hexamethylene diamine as a crosslinker. Results also show that the reaction can be controlled by either the DMTMM or the amine concentration so that a specific degree of substitution or crosslinking is achieved. The stability of DMTMM has also been examined, and degradation studies of DMTMM in H2O at 50 °C with 1H NMR analysis show that 11% of the starting material remains after 48 hours. The reaction has proven to be an effective alternative to other modification methods with cheap reagents, simple procedures and the ability to control the amount of modification. Further investigations are nonetheless required in order to determine the full potential the DMTMM-activated amidation of HA.

  • 56.
    Sawadjoon, Supaporn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Palladium-Catalyzed Nucleophilic Substitution of Alcohols: Mechanistic Studies and Synthetic Applications2013Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis deals with the palladium-catalyzed nucleophilic substitution of π-activated alcohols in which the C–O bond of a non-manipulated hydroxyl group is cleaved. The thesis is divided in two chapters describing two different catalytic systems.

    Chapter 2 describes a heterogeneous palladium-catalyzed transfer hydrogenolysis of primary, secondary, and tertiary benzylic alcohols to generate the corresponding aromatic hydrocarbons using formic acid as the hydrogen donor. A detailed mechanistic investigation of this reaction has been conducted that establish the kinetic order of each reaction component and also the deuterium kinetic isotope effects. This data provide a mechanistic picture that the hydride transfer from formic acid to palladium, and not the C–O bond cleavage, is involved in the rate-determining step and that a catalytic amount of a base promotes the transfer hydrogenolysis.

    Chapter 3 describes the development, mechanistic studies and synthetic scope of a homogeneous palladium-catalyzed amination of allylic alcohols. Isolation of the catalyst precursor and equilibrium studies of the palladium and π-acidic triphenylphosphite ligand show unique properties of this catalytic system. Stereochemical, kinetic, and kinetic isotope studies have been performed to provide insight into the mechanism of C–O bond cleavage of allylic alcohol and C–N bond formation catalyzed by the palladium complex. Interestingly, both O–H and C–O bond cleavages are involved in rate-determining steps.

    Delarbeid
    1. Pd-Catalyzed Transfer Hydrogenolysis of Primary, Secondary, and Tertiary Benzylic Alcohols by Formic Acid: A Mechanistic Study
    Åpne denne publikasjonen i ny fane eller vindu >>Pd-Catalyzed Transfer Hydrogenolysis of Primary, Secondary, and Tertiary Benzylic Alcohols by Formic Acid: A Mechanistic Study
    2013 (engelsk)Inngår i: ACS Catalysis, ISSN 2155-5435, Vol. 3, nr 4, s. 635-642Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    A palladium-catalyzed transfer hydrogenolysis of primary, secondary, and tertiary benzylic alcohols by formic acid has been developed and studied. The product hydrocarbons were obtained in excellent yields from bothsecondary and tertiary benzylic alcohols and in good yields for primary benzylicalcohols. The rate of disappearance of 1-phenylethanol (1) follows zero-order dependence in 1 and first-order dependence in formic acid and palladium. Catalytic amounts of base inhibit a competing disproportionation reaction ofalcohol to alkane and ketone, and an optimum was obtained when 5 equiv ofbase to palladium was used Deuterium kinetic isotope studies for the transferhydrogenolysis reveal individual isotope effects for the hydridic position (k(CHOH)/k(CDOH) = 2.26 +/- 0.24) and the protic position (k(CHOH)/k(CHOD) = 0.62 +/- 0.06) of the formic acid. Simultaneous deuteration in both positions offormic acid gave a combined isotope effect of (k(CHOH)/k(CDOD) = 1.41 +/- 0.11). We propose a mechanism involving the following steps: a competitive inhibition of the open palladium site by adsorption of the formate anion to generate formato-palladium species, followed by a reversible protonation and arate-limiting hydride transfer to obtain the active palladium with chemisorbed hydrogen that performs the hydrogenolysis of the alcohol in a fast reaction step.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-196658 (URN)10.1021/cs300785r (DOI)000317328000024 ()
    Forskningsfinansiär
    The Swedish Energy Agency
    Tilgjengelig fra: 2013-03-12 Laget: 2013-03-12 Sist oppdatert: 2014-01-23bibliografisk kontrollert
    2. An atom efficient route to N-aryl and N-alkyl pyrrolines by transition metal catalysis
    Åpne denne publikasjonen i ny fane eller vindu >>An atom efficient route to N-aryl and N-alkyl pyrrolines by transition metal catalysis
    2011 (engelsk)Inngår i: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 9, nr 7, s. 2548-2554Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    The synthesis of N-aryl, N-tosyl, and N-alkyl pyrrolines from allyl alcohols and amines has been developed. The reaction sequence includes a palladium-catalyzed allylation step in which non-manipulated allyl alcohol is used to generate the diallylated amine in good to excellent yield. An excess of allyl alcohol was necessary for efficient diallylation of the amine, where the excess alcohol could be recycled three times. For aryl and tosyl amines, Pd[P(OPh)(3)](4) was used and for benzyl and alkyl amines a catalytic system comprising Pd(OAc)(2), (PBu3)-Bu-n, and BEt3 was used. Both the electronic properties and the steric influence of the amine affected the efficiency of the allylation. The isolated diallylated amines were transformed into their corresponding pyrrolines by ring-closing metathesis catalyzed by (H(2)IMes)(PCy3)Cl2RuCHPh in good to excellent yield. A one-pot reaction was developed in which aniline was transformed into the corresponding pyrroline without isolating the diallylated intermediate. This one-pot reaction was successfully scaled-up to 1 mL of aniline in which the N-phenyl pyrroline was isolated in 95% yield. The versatility of the reaction in which 3-methyl-1-phenyl pyrroline was prepared in two-steps was demonstrated.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-150726 (URN)10.1039/c0ob00383b (DOI)000288456700063 ()21344095 (PubMedID)
    Tilgjengelig fra: 2011-04-05 Laget: 2011-04-05 Sist oppdatert: 2017-12-11bibliografisk kontrollert
    3.
    Posten ble ikke funnet. Det kan skyldes at posten ikke lenger er tilgjengelig eller det er feil id i adressefeltet.
    4. Equilibrium Study of Pd(dba)2 and P(OPh)3 in the Pd-Catalyzed Allylation of Aniline by Allyl Alcohol
    Åpne denne publikasjonen i ny fane eller vindu >>Equilibrium Study of Pd(dba)2 and P(OPh)3 in the Pd-Catalyzed Allylation of Aniline by Allyl Alcohol
    Vise andre…
    2014 (engelsk)Inngår i: Organometallics, ISSN 0276-7333, E-ISSN 1520-6041, Vol. 33, nr 1, s. 249-253Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Reaction of Pd(dba)2 and P(OPh)3 shows a unique equilibrium where the Pd[P(OPh)3]3 complex is favored over both Pd(dba)[P(OPh)3]2 and Pd[P(OPh)3]4 complexes at room temperature. At a lower temperature, Pd[P(OPh)3]4 becomes the most abundant complex in solution. X-ray studies of Pd[P(OPh)3]3 and Pd(dba)[P(OPh)3]2 complexes show that both complexes have a trigonal geometry with a Pd–P distance of 2.25 Å due to the π-acidity of the phosphite ligand. In solution, pure Pd(dba)[P(OPh)3]2 complex equilibrates to the favored Pd[P(OPh)3]3 complex, which is the most stable complex of those studied, and also forms the most active catalytic species. This catalyst precursor dissociates one ligand to give the reactive Pd[P(OPh)3]2, which performs an oxidative addition of nonmanipulated allyl alcohol to generate the π-allyl-Pd[P(OPh)3]2 intermediate according to ESI-MS studies.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-218947 (URN)10.1021/om4009873 (DOI)000329879900029 ()
    Tilgjengelig fra: 2014-02-27 Laget: 2014-02-20 Sist oppdatert: 2017-12-05bibliografisk kontrollert
  • 57.
    Sawadjoon, Supaporn
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Galkin, Maxim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Dahlstrand, Christian
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Rohde, Volker
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Samec, Joseph S. M.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Selective palladium-catalyzed reductive cleavage of beta-O-4-glucolaryl ether linkages in lignin model compounds2013Inngår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 245, s. 15-ORGN-Artikkel i tidsskrift (Annet vitenskapelig)
  • 58.
    Sawadjoon, Supaporn
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Lundstedt, Anna
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Fysikalisk-organisk kemi.
    Samec, Joseph
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Pd-Catalyzed Transfer Hydrogenolysis of Primary, Secondary, and Tertiary Benzylic Alcohols by Formic Acid: A Mechanistic Study2013Inngår i: ACS Catalysis, ISSN 2155-5435, Vol. 3, nr 4, s. 635-642Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A palladium-catalyzed transfer hydrogenolysis of primary, secondary, and tertiary benzylic alcohols by formic acid has been developed and studied. The product hydrocarbons were obtained in excellent yields from bothsecondary and tertiary benzylic alcohols and in good yields for primary benzylicalcohols. The rate of disappearance of 1-phenylethanol (1) follows zero-order dependence in 1 and first-order dependence in formic acid and palladium. Catalytic amounts of base inhibit a competing disproportionation reaction ofalcohol to alkane and ketone, and an optimum was obtained when 5 equiv ofbase to palladium was used Deuterium kinetic isotope studies for the transferhydrogenolysis reveal individual isotope effects for the hydridic position (k(CHOH)/k(CDOH) = 2.26 +/- 0.24) and the protic position (k(CHOH)/k(CHOD) = 0.62 +/- 0.06) of the formic acid. Simultaneous deuteration in both positions offormic acid gave a combined isotope effect of (k(CHOH)/k(CDOD) = 1.41 +/- 0.11). We propose a mechanism involving the following steps: a competitive inhibition of the open palladium site by adsorption of the formate anion to generate formato-palladium species, followed by a reversible protonation and arate-limiting hydride transfer to obtain the active palladium with chemisorbed hydrogen that performs the hydrogenolysis of the alcohol in a fast reaction step.

  • 59.
    Sawadjoon, Supaporn
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Samec, Joseph S. M.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Mechanistic studies and synthetic applications of palladium-catalyzed direct aminations of allylic alcohols2013Inngår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 245, s. 645-ORGN-Artikkel i tidsskrift (Annet vitenskapelig)
  • 60.
    Sawadjoon, Supaporn
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Sjöberg, Per J R
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Analytisk kemi.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Matsson, Olle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Fysikalisk-organisk kemi.
    Samec, Joseph S M
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Mechanistic Insights into the Pd-Catalyzed Direct Amination of Allyl Alcohols: Evidence for an Outer-sphere Mechanism Involving a Palladium Hydride Intermediate2014Inngår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 20, nr 6, s. 1520-1524Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The mechanism of direct amination of allyl alcohol by a palladium triphenylphosphite complex has been explored. Labelling studies show that the reaction proceeds through a π-allylpalladium intermediate. A second-order dependence of reaction rate on allyl alcohol concentration was observed. Kinetic isotope effect studies and ESI-MS studies are in agreement with a reaction proceeding through a palladium hydride intermediate in which both O-H bond and C-O bond cleavages are involved in rate-determining steps. A stereochemical study supports an outer-sphere nucleophilic attack of the π-allylpalladium intermediate giving complete chiral transfer from starting material to product.

  • 61.
    Singh, Vijay P
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Poon, Jia-fei
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Butcher, Ray J.
    Department of Chemistry, Howard University, USA..
    Lu, Xi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Mestres, Gemma
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Karlsson Ott, Marjam
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Engman, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Effect of a Bromo Substituent on the Glutathione Peroxidase Activity of a Pyridoxine-like Diselenide2015Inngår i: The Journal of Organic Chemistry, Vol. 50, nr 15, s. 7385-7395Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In search for better mimics of the glutathioneperoxidase enzymes, pyridoxine-like diselenides 6 and 11,carrying a 6-bromo substituent, were prepared. Reaction of2,6-dibromo-3-pyridinol 5 with sodium diselenide provided 6via aromatic nucleophilic substitution of the 2-bromosubstituent. LiAlH4 caused reduction of all four ester groupsand returned 11 after acidic workup. The X-ray structure of 6showed that the dipyridyl diselenide moiety was kept in analmost planar, transoid conformation. According to NBOanalysis,this was due to weak intramolecular Se···O (1.1 kcal/mol) and Se···N-interactions (2.5 kcal/mol). That the 6-bromo substituent increased the positive charge on seleniumwas confirmed by NPA-analysis and seen in calculated andobserved 77Se NMR-shifts. Diselenide 6 showed a more than 3-fold higher reactivity than the corresponding des-bromocompound 3a and ebselen when evaluated in the coupled reductase assay. Experiments followed for longer time (2 h) confirmedthat diselenide 6 is a better GPx-catalyst than 11. On the basis of 77Se-NMR experiments, a catalytic mechanism for diselenide 6was proposed involving selenol, selenosulfide and seleninic acid intermediates. At low concentration (10 μM) where it showedonly minimal toxicity, it could scavenge ROS produced by MNC- and PMNC-cells more efficiently than Trolox.

  • 62.
    Singh, Vijay P.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Poon, Jia-fei
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Engman, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Turning Pyridoxine into a Catalytic Chain-Breaking and Hydroperoxide-Decomposing Antioxidant2013Inngår i: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 78, nr 4, s. 1478-1487Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Vitamin B6 is involved in a variety of enzymatic transformations. Some recent findings also indicate an antioxidant role of the vitamin in biological systems. We set out to turn pyridoxine (la) into a catalytic chain-breaking and hydroperoxide-decomposing antioxidant by replacing the 2-methyl substituent with an alkyltelluro group. Target molecules 12 and derivatives 14, 17, 18, and 20 thereof were accessed by subjecting suitably substituted 2-halopyridin-3-ols to aromatic substitution using sodium alkanetellurolates as nucleophiles and then LAH-reduction of ester groups. The novel pyridoxine compounds were found to inhibit azo-initiated peroxidation of linoleic acid an order of magnitude more efficiently than alpha-tocopherol in a water/chlorobenzene two-phase system containing N-acetylcysteine as a reducing agent in the aqueous phase. The most lipid-soluble pyridoxine derivative 20c was regenerable and could inhibit peroxidation for substantially longer time (>410 min) than alpha-tocopherol (87 min). The chalcogen-containing pyridoxines could also mimic the action of the glutathione peroxidase enzymes. Thus, compound 20a catalyzed reduction of hydrogen peroxide three times more efficiently than Ebselen in the presence of glutathione as a stoichiometric reducing agent

  • 63.
    Singh, Vijay
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Poon, Jia-fei
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Butcher, Ray
    Dpt of Chemistry, Howard University.
    Engman, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Pyridoxine-derived organoselenium compounds with glutathione peroxidase-like and chain-breaking antioxidant activity2014Inngår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 20, nr 39, s. 12563-12571Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    One of the vitamin B6 vitamers, pyridoxine, wasmodified to incorporate selenium in various oxidation statesin place of the methyl group in position 2. Such compoundswere conveniently accessed by treatment of bis-4,5-(carbo-ethoxy)-2-iodo-3-pyridinol with disodium diselenide andLiAlH4-reduction. After work-up, selone7was isolated ingood yield as an air-stable crystalline material. Hydrogenbonding to the neighboring hydroxyl group, as revealed bythe short intramolecular Se···H distance in the crystal struc-ture is likely to provide extra stabilization to the compound.Computational studies showed that selone7is more stablethan the corresponding selenol tautomer by 12.2 kcalmol1.Hydrogen peroxide oxidation of the selone7afforded di-selenide12, and, on further oxidation, seleninic acid13.Treatment of the seleninic acid with thiophenol provided anisolable selenosulfide14. The glutathione peroxidase-likeproperties of the pyridoxine-derived compounds were as-sessed by using the coupled reductase method. Seleninicacid13was found to be twofold more active than ebselen.The chain-breaking capacity of the pyridoxine compoundswere studied in a water/chlorobenzene membrane modelcontaining linoleic acid as an oxidizable substrate andN-ace-tylcysteine as a thiol reducing agent. Diselenide15couldmatcha-tocopherol when it comes to reactivity towardsperoxyl radicals and inhibition time.

  • 64.
    Sjödin, Martin
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Karlsson, Christoffer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Huang, Hao
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Olsson, Henrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Yang, Li
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Gogoll, Adolf
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Nyholm, Leif
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Strömme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Organic Battery Materials based on Conducting Polymer Backbones with High Capacity Pending Groups2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Organic matter based battery materials have attracted large interest due to their inherent ability to provide an environmentally benign alternative to inorganic batteries because such materials can be produced from renewable resources via eco-efficient processes. The development of organic battery materials rely on several key factors that need to be resolved, the most important being dissolution problems, limited electronic conductivity, degradation of active material and slow redox kinetics. Conducting polymers are insoluble in most electrolytes, they are electronically conducting and show fast redox conversion but are, to some extent, unstable and have insufficient charge capacities for battery applications.

                To understand the instability of conducting polymers we have measured self discharge rates in polypyrrole at different temperatures. From these experiments it is clear that the self-discharge originates from an activated redox reaction with an activation barrier of around 0.4 eV. Although the exact nature of the redox reaction has not been identified we have been able to link the self discharge to, what is commonly referred to as, over-oxidation. Over-oxidation is common to polyacetylene, polyparaphenylene, polypyrrole and polythiophene and this mechanism of self discharge is thus a general feature of conducting polymers. This self-discharge mechanism is suppressed by low polymer doping levels, low potentials and low temperatures.     

    By attaching high capacity redox active groups onto the conducting polymer backbone the charge capacity can be increased while retaining electronic conductivity and insolubility. We have attached quinone groups to each repeat unit of polypyrrole for this purpose. Interestingly, in-situ spectroscopic measurements show that during quinone redox conversion the polymer doping level is in-fact reduced. Since the doping level of the polymer affects the rate of self-discharge the attachment of quinone units to the polypyrrole chain not only increases the charge capacity but also provides a conceptual strategy to control self discharge. 

  • 65.
    Sjödin, Martin
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Karlsson, Christoffer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Huang, Hao
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Yang, Li
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Huang, Xiao
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Strömme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Emanielsson, Rikard
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Gogoll, Adolf
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Rational design of conducting redox polymers for electrical energy storage2015Konferansepaper (Fagfellevurdert)
  • 66.
    Sjödin, Martin
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Karlsson, Christoffer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Huang, Hao
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Yang, Li
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Xiao, Huang
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Strömme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Emanuelsson, Rikard
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Gogoll, Adolf
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Design principles for constructing conducting redox polymer based battery materials2015Konferansepaper (Fagfellevurdert)
  • 67.
    Tibbelin, Julius
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Wallner, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Emanuelsson, Rikard
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Fysikalisk-organisk kemi.
    Heijkenskjöld, Filip
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Rosenberg, Martin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Yamazaki, Kaoru
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Nauroozi, Djawed
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Karlsson, Leif
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Feifel, Raimund
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Pettersson, Roland
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Analytisk kemi.
    Baumgartner, Judith
    Ott, Sascha
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Ottosson, Henrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    1,4-Disilacyclohexa-2,5-diene: a molecular building block that allows for remarkably strong neutral cyclic cross-hyperconjugation2014Inngår i: Chemical Science, ISSN 2041-6520, Vol. 5, nr 1, s. 360-371Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    2,3,5,6-Tetraethyl-1,4-disilacyclohexa-2,5-dienes with either four chloro (1a), methyl (1b), or trimethylsilyl (TMS) (1c) substituents at the two silicon atoms were examined in an effort to design rigid compounds with strong neutral cross-hyperconjugation between pi- and sigma-bonded molecular segments arranged into a cycle. Remarkable variations in the lowest electronic excitation energies, lowest ionization energies, and the first oxidation potentials were observed upon change of substituents, as determined by gas phase ultraviolet (UV) absorption spectroscopy, ultraviolet photoelectron spectroscopy (UPS), and cyclic voltammetry. A particularly strong neutral cyclic cross-hyperconjugation was observed in 1c. Its lowest electron binding energy (7.1 eV) is distinctly different from that of 1b (8.5 eV). Molecular orbital analysis reveals a stronger interaction between filled pi(C=C) and pi(SiR2) group orbitals in 1c than in 1a and 1b. The energy shift in the highest occupied molecular orbital is also reflected in the first oxidation potentials as observed in the cyclic voltammograms of the respective compounds (1.47, 0.88, and 0.46 V for 1a, 1b and 1c, respectively). Furthermore, 1,4-disilacyclohexadiene 1c absorbs strongly at 273 nm (4.55 eV), whereas 1a and 1b have no symmetry allowed excitations above 215 nm (below 5.77 eV). Thus, suitably substituted 1,4-disilacyclohexa-2,5-dienes could represent novel building blocks for the design of larger cross-hyperconjugated molecules as alternatives to traditional purely cross-p-conjugated analogues, and could allow for design of molecules with properties that are not accessible to those that are exclusively pi-conjugated.

  • 68.
    Tšupova, Svetlana
    et al.
    Ruprecht-Karls-Universität Heidelberg.
    Cadu, Alban
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Stuck, Fabian
    Ruprecht-Karls-Universität Heidelberg.
    Rominger, Frank
    Ruprecht-Karls-Universität Heidelberg.
    Rudolph, Matthias
    Ruprecht-Karls-Universität Heidelberg.
    Samec, Joseph
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi. Stockholm University.
    Hashmi, A. Stephen K.
    Ruprecht-Karls-Universität Heidelberg.
    Dual Gold (I) Catalysed Cyclisation of Dialkynyl Pyridinium saltsManuskript (preprint) (Annet vitenskapelig)
    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.

  • 69.
    Verendel, J. Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Transition Metal Catalysis for Selective Synthesis and Sustainable Chemistry2012Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis discusses the preparation and use of transition-metal catalysts for selective organic chemical reactions. Specifically, two different matters have been studied; the asymmetric hydrogenation of carbon-carbon double bonds using N,P-ligated iridium catalysts and the metal-catalyzed transfer of small molecules from biomass to synthetic intermediates.

    In the first part of this thesis, chiral N,P-ligands were synthesized and evaluated in iridium catalysts for the asymmetric hydrogenation of non- and weakly functionalized alkenes (Papers I & II). The new catalysts were prepared via chiral-pool strategies and exhibited superior properties for the reduction of certain types of alkenes. In particular, some of the catalysts showed excellent activity and selectivity in the enantioselective reduction of terminal alkenes, and the preparation of a modular catalyst library allowed the asymmetric hydrogenation of a wide range of 1,1-disubstituted alkenes with unprecedented efficiency and enantioselectivity (Paper III). Methods for the selective preparation of chiral hetero- and carbocyclic fragments using iridium-catalyzed asymmetric hydrogenation as an enantiodetermining key step were also developed. A range of elusive chiral building blocks that have applications in pharmaceutical and natural-product chemistry could thus be conveniently prepared (Papers IV & V).

    The second part of this thesis deals with the catalytic decomposition of polysaccharides into sugar alcohols and the incorporation of their decomposition products into alkene substrates. Iridium-catalyzed dehydrogenative decarbonylation was found to decompose polyols into CO:H2 mixtures that could be used immediately in the ex situ low-pressure hydroformylation of styrene (Paper VI). The net process was thus the hydroformylation of alkenes with biomass-derived synthesis gas.

    Delarbeid
    1. Development of pinene-derived N,P ligands and their utility in catalytic asymmetric hydrogenation
    Åpne denne publikasjonen i ny fane eller vindu >>Development of pinene-derived N,P ligands and their utility in catalytic asymmetric hydrogenation
    2007 (engelsk)Inngår i: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, nr 47, s. 5603-5610Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    New diastereomeric N,P-ligands, derived from the natural product (+)--pinene, have been synthesized and evaluated in iridium-catalyzed asymmetric hydrogenation. The ligands are tetrahydroquinoline derivatives synthesized directly from commercially available -pinene utilizing resolution or recrystallization to separate diastereomers. In reduction of a range of different trisubstituted alkenes the catalysts express very different activities ranging from no activity to high activity. One of the catalysts gives good ee values for some substrates.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-12344 (URN)10.1039/b713257n (DOI)000251269100016 ()
    Tilgjengelig fra: 2007-12-13 Laget: 2007-12-13 Sist oppdatert: 2017-12-11bibliografisk kontrollert
    2. Biaryl phosphite-oxazolines from hydroxyl aminoacid derivatives: highly efficient modular ligands for Ir-catalyzed hydrogenation of alkenes
    Åpne denne publikasjonen i ny fane eller vindu >>Biaryl phosphite-oxazolines from hydroxyl aminoacid derivatives: highly efficient modular ligands for Ir-catalyzed hydrogenation of alkenes
    Vise andre…
    2008 (engelsk)Inngår i: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, nr 33, s. 3888-3890Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    High enantioselectivities and activities are achieved in the Ir-catalyzed hydrogenation of several unfunctionalized olefins using modular biaryl phosphite-oxazoline ligands from hydroxyl aminoacid derivatives, the presence of a biaryl phosphite group is crucial to this success.

    Emneord
    reduction, hydrogenation, diastereoselective syntheses, enantioselective syntheses (incl. cis/trans-isomerism), polyphenylalkane derivatives, carboxylic acid esters (benzene compounds), alcohols (benzene compounds)
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-17849 (URN)10.1039/b806891g (DOI)000258686400015 ()
    Tilgjengelig fra: 2008-09-08 Laget: 2008-09-08 Sist oppdatert: 2017-12-08bibliografisk kontrollert
    3. Iridium phosphite-oxazoline catalysts for the highly enantioselective hydrogenation of terminal alkenes
    Åpne denne publikasjonen i ny fane eller vindu >>Iridium phosphite-oxazoline catalysts for the highly enantioselective hydrogenation of terminal alkenes
    Vise andre…
    2009 (engelsk)Inngår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 131, nr 34, s. 12344-12353Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    A modular library of readily available phosphite-oxazoline ligands (L1-L16a-f) has been successfully applied for the first time in the Ir-catalyzed asymmetric hydrogenation of a broad range of highly unfunctionalized 1,1,-disubstituted terminal alkenes. Enantioselectivities up to >99% and full conversions were obtained in several 1,1-disubstituted alkenes, including substrate classes that have never been asymmetrically hydrogenated before (i.e., 1,1-heteoraryl-alkyl, 1,1-diaryl, trifluoromethyl, etc.). The results indicated that these catalytic systems have high tolerance to the steric and electronic requirements of the substrate and also to the presence of a neighboring polar group. The asymmetric hydrogenations were also performed using propylene carbonate as solvent, which allowed the Ir catalyst to be reused and maintained the excellent enantioselectivities.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-121863 (URN)10.1021/ja904152r (DOI)000269379600068 ()19658416 (PubMedID)
    Tilgjengelig fra: 2010-03-31 Laget: 2010-03-31 Sist oppdatert: 2017-12-12bibliografisk kontrollert
    4. Highly Flexible Synthesis of Chiral Azacycles via Iridium-Catalyzed Hydrogenation
    Åpne denne publikasjonen i ny fane eller vindu >>Highly Flexible Synthesis of Chiral Azacycles via Iridium-Catalyzed Hydrogenation
    Vise andre…
    2010 (engelsk)Inngår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 132, nr 26, s. 8880-8881Artikkel i tidsskrift (Fagfellevurdert) 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.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-135809 (URN)10.1021/ja103901e (DOI)000279561200033 ()20557052 (PubMedID)
    Tilgjengelig fra: 2010-12-09 Laget: 2010-12-08 Sist oppdatert: 2017-12-11bibliografisk kontrollert
    5. Chiral Hetero- and Carbocyclic Compounds from the Asymmetric Hydrogenation of Cyclic Alkenes
    Åpne denne publikasjonen i ny fane eller vindu >>Chiral Hetero- and Carbocyclic Compounds from the Asymmetric Hydrogenation of Cyclic Alkenes
    Vise andre…
    2012 (engelsk)Inngår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, nr 21, s. 6507-6513Artikkel i tidsskrift (Fagfellevurdert) 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.

    Emneord
    asymmetric synthesis, heterocyclic compounds, homogeneous catalysis, hydrogenation, iridium
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-175620 (URN)10.1002/chem.201104073 (DOI)000304045000016 ()
    Tilgjengelig fra: 2012-06-12 Laget: 2012-06-11 Sist oppdatert: 2017-12-07bibliografisk kontrollert
    6. Selective, metal-catalyzed transfer of H2 and CO from polyols to alkenes
    Åpne denne publikasjonen i ny fane eller vindu >>Selective, metal-catalyzed transfer of H2 and CO from polyols to alkenes
    2013 (engelsk)Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 6, nr 3, s. 426-429Artikkel i tidsskrift (Fagfellevurdert) Published
    Emneord
    catalysis, transition metals, renewable feedstocks
    HSV kategori
    Forskningsprogram
    Organisk kemi
    Identifikatorer
    urn:nbn:se:uu:diva-182817 (URN)10.1002/cssc.201200843 (DOI)000315715400008 ()
    Tilgjengelig fra: 2012-10-15 Laget: 2012-10-15 Sist oppdatert: 2017-12-07bibliografisk kontrollert
  • 70.
    Verendel, J. Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Diner, Peter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Efficient, Low Temperature Production of Hydrogen from Methanol2013Inngår i: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 5, nr 10, s. 2795-2797Artikkel i tidsskrift (Annet vitenskapelig)
  • 71.
    Verendel, J. Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Li, Jia-Qi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Quan, Xu
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Peters, Byron
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Zhou, Taigang
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Gautun, Odd R.
    Govender, Thavendran
    Andersson, Pher G.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Chiral Hetero- and Carbocyclic Compounds from the Asymmetric Hydrogenation of Cyclic Alkenes2012Inngår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, nr 21, s. 6507-6513Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 72.
    Verendel, J. Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Nordlund, Michael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Andersson, Pher G.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Selective, metal-catalyzed transfer of H2 and CO from polyols to alkenes2013Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 6, nr 3, s. 426-429Artikkel i tidsskrift (Fagfellevurdert)
  • 73.
    Watile, Rahul
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Biswas, Srijit
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Samec, Joseph
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    An aqueous and recyclable copper(I)-catalyzed route to α-sulfenylated carbonyl compounds from propargylic alcohols and aryl thiols2013Inngår i: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 15, nr 11, s. 3176-3179Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A highly efficient one-step copper(I)-catalyzed method for the synthesis of α-sulfenylated carbonyl compounds from propargylic alcohols and aryl thiols in aqueous media is described. A variety of α-sulfenylated carbonyl compounds can be synthesized in good to excellent yields. The catalyst has been successfully recycled up to 4 times without any loss of activity in an aqueous medium.

  • 74.
    Yang, Li
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Huang, Xiao
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Gogoll, Adolf
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Strömme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Sjödin, Martin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Effect of the Linker in Terephthalate-Functionalized Conducting Redox PolymersManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    The combination of high capacity redox active pendent groups and conducting polymers, realized in conducting redox polymers (CRPs), provides materials with high charge storage capacity that are electronically conducting whichmakes CRPs attractive for electrical energy storage applications. In this report, six polythiophene and poly(3,4-ethylenedioxythiophene)(PEDOT)-based CRPs with a diethyl terephthalate unit covalently bound to the polymer chain byvarious linkers have been synthesized and characterized electrochemically. The effects of the choice of polymer backboneand of the nature of the link on the electrochemistry, and in particular the cycling stability of these polymers, are discussed.All CRPs show both the doping of the polymer backbone as well as the redox behavior of the pendent groups and the redoxpotential of the pendent groups in the CRPs is close to that of corresponding monomer, indicating insignificant interactionbetween the pendant and the polymer backbone. While all CRPs show various degrees of charge decay upon electrochemical redox conversion, the PEDOT-based CRPs show significantly improved stability compared to the polythiophene counterparts. Moreover, we show that by the right choice of link the cycling stability of diethyl terephthalate substituted PEDOTbased CRPS can be significantly improved.

  • 75.
    Yang, Li
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Huang, Xiao
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Gogoll, Adolf
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Strömme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Sjödin, Martin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Green Energy Storage Material-Thiophene-based Terephthalate redox Polymer2014Konferansepaper (Fagfellevurdert)
  • 76.
    Zhou, Taigang
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Asymmetric Hydrogenation of Functionalized Olefins Using N,P-Ligated Iridium Complexes2012Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Transition-metal-catalyzed asymmetric hydrogenation is one of the most efficient, straightforward, and well-established methods for preparing enantiomerically enriched compounds. Over the past decades, significant progress has been made with iridium, rhodium and ruthenium complexes to asymmetric hydrogenate a selection of olefins, such as, α,β-unsaturated carboxylic acid derivatives, ketones, imines and phosphonates. Although these metals have been applied successfully in the hydrogenation of olefins, they differ in their substrate tolerance.  Ruthenium and rhodium based catalysts require a coordinating group in the vicinity of the C=C bond. However, iridium based catalysts do not require this coordinating group, hence, asymmetric hydrogenation with iridium catalysts has been widely used for both functionalized and unfunctionalized olefin substrates. This thesis focuses on expanding the substrate scope for asymmetric hydrogenation using chiral N,P-ligated iridium catalysts. Papers I and II investigate the asymmetric hydrogenation of prochiral N-heterocyclic compounds prepared by ring-closing metathesis using the iridium catalysts developed in our group.  These substrates are interesting as they bear resemblance to pharmaceutically active compounds and therefore have tremendous value in medicinal chemistry.  Excellent enantioselectivities, up to >99% ee and conversions were obtained. In papers III and IV we synthesized many unsaturated acyclic and cyclic sulfones with varying substitution patterns.  The sulfones were subjected to hydrogenation using our N,P-ligated iridium catalysts, producing the chiral sulfone products in high enantiomeric excess (up to 99% ee). This methodology was combined with the Ramberg-Bäcklund reaction, offering a novel route to chiral allylic and homoallylic compounds. In addition to obtaining these chiral compounds in good yields, no decrease in enantiomeric excess was observed after the Ramberg-Bäcklund reaction. This strategy has been applied in the preparation of the chiral building block for renin inhibitors.

    Delarbeid
    1. Highly Flexible Synthesis of Chiral Azacycles via Iridium-Catalyzed Hydrogenation
    Åpne denne publikasjonen i ny fane eller vindu >>Highly Flexible Synthesis of Chiral Azacycles via Iridium-Catalyzed Hydrogenation
    Vise andre…
    2010 (engelsk)Inngår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 132, nr 26, s. 8880-8881Artikkel i tidsskrift (Fagfellevurdert) 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.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-135809 (URN)10.1021/ja103901e (DOI)000279561200033 ()20557052 (PubMedID)
    Tilgjengelig fra: 2010-12-09 Laget: 2010-12-08 Sist oppdatert: 2017-12-11bibliografisk kontrollert
    2. Chiral Hetero- and Carbocyclic Compounds from the Asymmetric Hydrogenation of Cyclic Alkenes
    Åpne denne publikasjonen i ny fane eller vindu >>Chiral Hetero- and Carbocyclic Compounds from the Asymmetric Hydrogenation of Cyclic Alkenes
    Vise andre…
    2012 (engelsk)Inngår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, nr 21, s. 6507-6513Artikkel i tidsskrift (Fagfellevurdert) 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.

    Emneord
    asymmetric synthesis, heterocyclic compounds, homogeneous catalysis, hydrogenation, iridium
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-175620 (URN)10.1002/chem.201104073 (DOI)000304045000016 ()
    Tilgjengelig fra: 2012-06-12 Laget: 2012-06-11 Sist oppdatert: 2017-12-07bibliografisk kontrollert
    3. Enantioselective Synthesis of Chiral Sulfones by Ir-Catalyzed Asymmetric Hydrogenation: A Facile Approach to the Preparation of Chiral Allylic and Homoallylic Compounds
    Åpne denne publikasjonen i ny fane eller vindu >>Enantioselective Synthesis of Chiral Sulfones by Ir-Catalyzed Asymmetric Hydrogenation: A Facile Approach to the Preparation of Chiral Allylic and Homoallylic Compounds
    Vise andre…
    2012 (engelsk)Inngår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 134, nr 33, s. 13592-13595Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    A highly efficient and enantioselective Ir-catalyzed hydrogenation of unsaturated sulfones was developed. Chiral cyclic and acyclic sulfones were produced in excellent enantioselectivities (up to 98% ee). Coupled with the Ramberg-Backlund rearrangement, this reaction offers a novel route to chiral allylic and homoallylic compounds in excellent enantioselectivities (up to 97% ee) and high yields (up to 94%).

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-182640 (URN)10.1021/ja306731u (DOI)000307699000016 ()
    Tilgjengelig fra: 2012-10-14 Laget: 2012-10-14 Sist oppdatert: 2017-12-07bibliografisk kontrollert
    4. High Enantioselectivity of Chiral Sulfones byIridium Catalyzed Asymmetric Hydrogenation: An Efficient Access for Total Synthesis of Imperanene
    Åpne denne publikasjonen i ny fane eller vindu >>High Enantioselectivity of Chiral Sulfones byIridium Catalyzed Asymmetric Hydrogenation: An Efficient Access for Total Synthesis of Imperanene
    (engelsk)Manuskript (preprint) (Annet vitenskapelig)
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-182643 (URN)
    Tilgjengelig fra: 2012-10-14 Laget: 2012-10-14 Sist oppdatert: 2012-11-12
  • 77.
    Zhou, Taigang
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Peters, Byron
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Cadu, Alban
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Andersson, Pher
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    High Enantioselectivity of Chiral Sulfones byIridium Catalyzed Asymmetric Hydrogenation: An Efficient Access for Total Synthesis of ImperaneneManuskript (preprint) (Annet vitenskapelig)
  • 78.
    Zhou, Taigang
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Peters, Byron
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Maldonado, Matias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Govender, Thavendran
    Department of Pharmacy, University of KwaZulu-Natal.
    Andersson, Pher
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Enantioselective Synthesis of Chiral Sulfones by Ir-Catalyzed Asymmetric Hydrogenation: A Facile Approach to the Preparation of Chiral Allylic and Homoallylic Compounds2012Inngår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 134, nr 33, s. 13592-13595Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A highly efficient and enantioselective Ir-catalyzed hydrogenation of unsaturated sulfones was developed. Chiral cyclic and acyclic sulfones were produced in excellent enantioselectivities (up to 98% ee). Coupled with the Ramberg-Backlund rearrangement, this reaction offers a novel route to chiral allylic and homoallylic compounds in excellent enantioselectivities (up to 97% ee) and high yields (up to 94%).

12 51 - 78 of 78
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