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Tsupova, S., Cadu, A., Stuck, F., Rominger, F., Rudolph, M., Samec, J. S. M. & Hashmi, A. S. (2017). Dual Gold(I)-catalyzed Cyclization of Dialkynyl Pyridinium Salts. ChemCatChem, 9(11), 1915-1920
Open this publication in new window or tab >>Dual Gold(I)-catalyzed Cyclization of Dialkynyl Pyridinium Salts
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2017 (English)In: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 9, no 11, p. 1915-1920Article in journal (Refereed) Published
Abstract [en]

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

Keywords
gold, isomerization, palladium, pyridine, reduction
National Category
Organic Chemistry
Identifiers
urn:nbn:se:uu:diva-326496 (URN)10.1002/cctc.201700018 (DOI)000403017800007 ()
Note

De 2 första författarna delar förstaförfattarskapet.

Available from: 2017-08-22 Created: 2017-08-22 Last updated: 2017-08-22Bibliographically approved
Cadu, A. (2016). Noble Metal Catalysed Reductions and Rearrangements. (Doctoral dissertation). Uppsala: Acta Universitatis Upsaliensis
Open this publication in new window or tab >>Noble Metal Catalysed Reductions and Rearrangements
2016 (English)Doctoral 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.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2016. p. 63
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1337
National Category
Organic Chemistry
Research subject
Chemistry with specialization in Organic Chemistry
Identifiers
urn:nbn:se:uu:diva-272383 (URN)978-91-554-9453-7 (ISBN)
Public defence
2016-02-25, B/B21, BMC, Husargatan 3, Uppsala, 09:30 (English)
Opponent
Supervisors
Available from: 2016-02-03 Created: 2016-01-13 Last updated: 2016-02-12
Peters, B. K., Zhou, T., Rujirawanich, J., Cadu, A., Singh, T., Rabten, W., . . . Andersson, P. G. (2014). An Enantioselective Approach to the Preparation of Chiral Sulfones by Ir-Catalyzed Asymmetric Hydrogenation. Journal of the American Chemical Society, 136(47), 16557-16562
Open this publication in new window or tab >>An Enantioselective Approach to the Preparation of Chiral Sulfones by Ir-Catalyzed Asymmetric Hydrogenation
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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
Cadu, A., Watile, R., Biswas, S., Orthaber, A., Sjöberg, P. J. & Samec, J. (2014). One-Pot Synthesis of Keto Thioethers by Palladium/Gold-Catalyzed Click and Pinacol Reactions. Organic Letters, 16(21), 5556-5559
Open this publication in new window or tab >>One-Pot Synthesis of Keto Thioethers by Palladium/Gold-Catalyzed Click and Pinacol Reactions
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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
Cadu, A. (2013). Iridium Catalysed Asymmetric Hydrogenation of Pyridines. (Licentiate dissertation). Uppsala: Uppsala universitet
Open this publication in new window or tab >>Iridium Catalysed Asymmetric Hydrogenation of Pyridines
2013 (English)Licentiate 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.

Place, publisher, year, edition, pages
Uppsala: Uppsala universitet, 2013. p. 34
Keywords
hydrogenation, pyridine, catalytic, Iridium
National Category
Organic Chemistry
Research subject
Organic Chemistry
Identifiers
urn:nbn:se:uu:diva-212413 (URN)
Presentation
2013-05-31, Uppsala, 12:41 (English)
Opponent
Supervisors
Available from: 2013-12-11 Created: 2013-12-10 Last updated: 2017-01-25Bibliographically approved
Cadu, A. & Andersson, P. G. (2013). Iridium catalysis: Application of asymmetric reductive hydrogenation. Dalton Transactions, 42(40), 14345-14356
Open this publication in new window or tab >>Iridium catalysis: Application of asymmetric reductive hydrogenation
2013 (English)In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 42, no 40, p. 14345-14356Article in journal (Refereed) Published
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.

Keywords
catalysis, iridium, review, organometallic, hydrogenation, asymmetric
National Category
Organic Chemistry
Research subject
Chemistry with specialization in Organic Chemistry
Identifiers
urn:nbn:se:uu:diva-209266 (URN)10.1039/c3dt51163d (DOI)000324931400001 ()
Available from: 2013-10-16 Created: 2013-10-16 Last updated: 2017-12-06Bibliographically approved
Cadu, A., Upadhyay, P. K. & Andersson, P. G. (2013). Iridium-Catalyzed Asymmetric Hydrogenation of Substituted Pyridines. Asian Journal of Organic Chemistry, 2(12), 1061-1065
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
Cadu, A. & Andersson, P. G. (2012). Development of iridium-catalyzed asymmetric hydrogenation: New catalysts, new substrate scope. Journal of Organometallic Chemistry, 714, 3-11
Open this publication in new window or tab >>Development of iridium-catalyzed asymmetric hydrogenation: New catalysts, new substrate scope
2012 (English)In: Journal of Organometallic Chemistry, ISSN 0022-328X, E-ISSN 1872-8561, Vol. 714, p. 3-11Article, review/survey (Refereed) Published
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)]

Keywords
review iridium catalyst asym hydrogenation alkene heteroarom
National Category
Organic Chemistry
Research subject
Chemistry
Identifiers
urn:nbn:se:uu:diva-187584 (URN)10.1016/j.jorganchem.2012.04.002 (DOI)000306239400003 ()
Available from: 2012-12-10 Created: 2012-12-07 Last updated: 2017-12-07Bibliographically approved
Cadu, A., Paptchikhine, A. & Andersson, P. G. (2011). Birch Reaction Followed by Asymmetric Iridium-Catalysed Hydrogenation. Synthesis (Stuttgart) (23), 3796-3800
Open this publication in new window or tab >>Birch Reaction Followed by Asymmetric Iridium-Catalysed Hydrogenation
2011 (English)In: Synthesis (Stuttgart), ISSN 0039-7881, E-ISSN 1437-210X, no 23, p. 3796-3800Article in journal (Refereed) Published
Abstract [en]

Birch reaction products are asymmetrically hydrogenated with high enantio- and diastereoselectivity via iridium catalysts. This new method of producing chiral compounds was explored for a variety of 1,3-di- and 1,2,4-tri-substituted cyclohexadienes.

Keywords
asymmetric catalysis, iridium, hydrogenation, reduction, radical reaction
National Category
Natural Sciences
Identifiers
urn:nbn:se:uu:diva-167652 (URN)10.1055/s-0031-1289569 (DOI)000298156900007 ()
Available from: 2012-02-01 Created: 2012-01-31 Last updated: 2017-12-08Bibliographically approved
Tšupova, S., Cadu, A., Stuck, F., Rominger, F., Rudolph, M., Samec, J. & Hashmi, A. S.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
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(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
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-7779-1849

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