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Noble Metal Catalysed Reductions and Rearrangements
Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi. (Joseph Samec)ORCID-id: 0000-0001-7779-1849
2016 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
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.

sted, utgiver, år, opplag, sider
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
HSV kategori
Forskningsprogram
Kemi med inriktning mot organisk kemi
Identifikatorer
URN: urn:nbn:se:uu:diva-272383ISBN: 978-91-554-9453-7 (tryckt)OAI: oai:DiVA.org:uu-272383DiVA, id: diva2:893887
Disputas
2016-02-25, B/B21, BMC, Husargatan 3, Uppsala, 09:30 (engelsk)
Opponent
Veileder
Tilgjengelig fra: 2016-02-03 Laget: 2016-01-13 Sist oppdatert: 2016-02-12
Delarbeid
1. Iridium-Catalyzed Asymmetric Hydrogenation of Substituted Pyridines
Åpne denne publikasjonen i ny fane eller vindu >>Iridium-Catalyzed Asymmetric Hydrogenation of Substituted Pyridines
2013 (engelsk)Inngår i: Asian Journal of Organic Chemistry, ISSN 2193-5807, Vol. 2, nr 12, s. 1061-1065Artikkel i tidsskrift (Fagfellevurdert) 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.

Emneord
hydrogenation, iridium, N-iminopyridium ylides, pyridines, selective catalysis
HSV kategori
Forskningsprogram
Organisk kemi
Identifikatorer
urn:nbn:se:uu:diva-212412 (URN)10.1002/ajoc.201300160 (DOI)000328218000008 ()
Tilgjengelig fra: 2013-12-10 Laget: 2013-12-10 Sist oppdatert: 2017-01-25bibliografisk kontrollert
2. An Enantioselective Approach to the Preparation of Chiral Sulfones by Ir-Catalyzed Asymmetric Hydrogenation
Åpne denne publikasjonen i ny fane eller vindu >>An Enantioselective Approach to the Preparation of Chiral Sulfones by Ir-Catalyzed Asymmetric Hydrogenation
Vise andre…
2014 (engelsk)Inngår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 136, nr 47, s. 16557-16562Artikkel i tidsskrift (Fagfellevurdert) 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.

sted, utgiver, år, opplag, sider
American Chemical Society (ACS), 2014
HSV kategori
Forskningsprogram
Organisk kemi
Identifikatorer
urn:nbn:se:uu:diva-236862 (URN)10.1021/ja5079877 (DOI)000345720500016 ()25300238 (PubMedID)
Tilgjengelig fra: 2014-11-24 Laget: 2014-11-24 Sist oppdatert: 2017-12-05bibliografisk kontrollert
3. One-Pot Synthesis of Keto Thioethers by Palladium/Gold-Catalyzed Click and Pinacol Reactions
Åpne denne publikasjonen i ny fane eller vindu >>One-Pot Synthesis of Keto Thioethers by Palladium/Gold-Catalyzed Click and Pinacol Reactions
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2014 (engelsk)Inngår i: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 16, nr 21, s. 5556-5559Artikkel i tidsskrift (Fagfellevurdert) 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.

sted, utgiver, år, opplag, sider
American Chemical Society (ACS), 2014
Emneord
Gold, Palladium, thioether, catalysis, synthesis
HSV kategori
Identifikatorer
urn:nbn:se:uu:diva-236857 (URN)10.1021/ol502553p (DOI)000344635200013 ()25325145 (PubMedID)
Tilgjengelig fra: 2014-11-24 Laget: 2014-11-24 Sist oppdatert: 2017-12-05bibliografisk kontrollert
4. Dual Gold (I) Catalysed Cyclisation of Dialkynyl Pyridinium salts
Åpne denne publikasjonen i ny fane eller vindu >>Dual Gold (I) Catalysed Cyclisation of Dialkynyl Pyridinium salts
Vise andre…
(engelsk)Manuskript (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.

Emneord
chemistry
HSV kategori
Forskningsprogram
Kemi med inriktning mot organisk kemi
Identifikatorer
urn:nbn:se:uu:diva-272369 (URN)
Tilgjengelig fra: 2016-01-13 Laget: 2016-01-13 Sist oppdatert: 2016-02-12bibliografisk kontrollert

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