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Iridium-Catalyzed Asymmetric Hydrogenation of Substituted Pyridines
Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för läkemedelskemi.
Stockholm University.
2013 (Engelska)Ingår i: Asian Journal of Organic Chemistry, ISSN 2193-5807, Vol. 2, nr 12, s. 1061-1065Artikel i tidskrift (Refereegranskat) 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.

Ort, förlag, år, upplaga, sidor
2013. Vol. 2, nr 12, s. 1061-1065
Nyckelord [en]
hydrogenation, iridium, N-iminopyridium ylides, pyridines, selective catalysis
Nationell ämneskategori
Organisk kemi Oorganisk kemi
Forskningsämne
Organisk kemi
Identifikatorer
URN: urn:nbn:se:uu:diva-212412DOI: 10.1002/ajoc.201300160ISI: 000328218000008OAI: oai:DiVA.org:uu-212412DiVA, id: diva2:677721
Tillgänglig från: 2013-12-10 Skapad: 2013-12-10 Senast uppdaterad: 2017-01-25Bibliografiskt granskad
Ingår i avhandling
1. Iridium Catalysed Asymmetric Hydrogenation of Pyridines
Öppna denna publikation i ny flik eller fönster >>Iridium Catalysed Asymmetric Hydrogenation of Pyridines
2013 (Engelska)Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
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.

Ort, förlag, år, upplaga, sidor
Uppsala: Uppsala universitet, 2013. s. 34
Nyckelord
hydrogenation, pyridine, catalytic, Iridium
Nationell ämneskategori
Organisk kemi
Forskningsämne
Organisk kemi
Identifikatorer
urn:nbn:se:uu:diva-212413 (URN)
Presentation
2013-05-31, Uppsala, 12:41 (Engelska)
Opponent
Handledare
Tillgänglig från: 2013-12-11 Skapad: 2013-12-10 Senast uppdaterad: 2017-01-25Bibliografiskt granskad
2. Noble Metal Catalysed Reductions and Rearrangements
Öppna denna publikation i ny flik eller fönster >>Noble Metal Catalysed Reductions and Rearrangements
2016 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
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.

Ort, förlag, år, upplaga, sidor
Uppsala: Acta Universitatis Upsaliensis, 2016. s. 63
Serie
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1337
Nationell ämneskategori
Organisk kemi
Forskningsämne
Kemi med inriktning mot organisk kemi
Identifikatorer
urn:nbn:se:uu:diva-272383 (URN)978-91-554-9453-7 (ISBN)
Disputation
2016-02-25, B/B21, BMC, Husargatan 3, Uppsala, 09:30 (Engelska)
Opponent
Handledare
Tillgänglig från: 2016-02-03 Skapad: 2016-01-13 Senast uppdaterad: 2016-02-12

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Förlagets fulltexthttp://dx.doi.org/10.1002/ajoc.201300160

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Cadu, AlbanUpadhyay, Puspesh K.

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