Larissa pauli (7 resultados)

PAP. Condición: New. New Book. Shipped from UK. THIS BOOK IS PRINTED ON DEMAND. Established seller since 2000.

PAP. Condición: New. New Book. Delivered from our UK warehouse in 4 to 14 business days. THIS BOOK IS PRINTED ON DEMAND. Established seller since 2000.

Taschenbuch. Condición: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -The main focus of the research presented in this dissertation was to broaden the substrate scope of the iridium-catalyzed asymmetric hydrogenation of heterocyclic compounds. In view of the fact that a widely applicable hydrogenation system for the reduction of structurally diverse furans and benzofurans is to date not available, a thorough investigation of furan, benzofuran and thiophene 1,1-dioxide derivatives was carried out. Mono- and disubstituted furan derivatives were synthesized and submitted to iridium-catalyzed hydrogenation reactions. While 3-substituted furans were reduced using a catalyst based on a cyclopentane-annulated bicyclic pyridine-phosphine ligand with high enantiomeric excess (95-99% ee) and conversion (83-99%), 2-substituted counterparts proved to be less reactive (80-97% conv., 65-82% ee) with the same catalyst. Asymmetric hydrogenation of 2,4-disubstituted furans proved to be challenging for several reasons, not least because of the problem of controlling the cis/trans selectivity. Surprisingly, in the iridium-catalyzed hydrogenation of 3-substituted benzofurans only one catalyst, based on the cyclohexane-annulated pyridine-phosphinite ligand, showed high activity and enantioselectivity (75-89% conv., 91-92% ee), whereas the five-membered ring analog suffered from moderate activity and enantioselectivity. In contrast, the 2-alkyl substituted benzofurans gave superior results (99% conv., 97-99% ee). Disubstituted thiophene 1,1-dioxides were also investigated in the iridium-catalyzed asymmetric hydrogenation. The hydrogenation of 3,4 disubstituted thiophene 1,1 dioxides using a catalyst based on a cyclopentane-annulated bicyclic pyridine-phosphine ligand gave inferior results to those obtained with their 2,5 disubstituted counterparts. 178 pp. Englisch.…

Taschenbuch. Condición: Neu. nach der Bestellung gedruckt Neuware - Printed after ordering - The main focus of the research presented in this dissertation was to broaden the substrate scope of the iridium-catalyzed asymmetric hydrogenation of heterocyclic compounds. In view of the fact that a widely applicable hydrogenation system for the reduction of structurally diverse furans and benzofurans is to date not available, a thorough investigation of furan, benzofuran and thiophene 1,1-dioxide derivatives was carried out. Mono- and disubstituted furan derivatives were synthesized and submitted to iridium-catalyzed hydrogenation reactions. While 3-substituted furans were reduced using a catalyst based on a cyclopentane-annulated bicyclic pyridine-phosphine ligand with high enantiomeric excess (95-99% ee) and conversion (83-99%), 2-substituted counterparts proved to be less reactive (80-97% conv., 65-82% ee) with the same catalyst. Asymmetric hydrogenation of 2,4-disubstituted furans proved to be challenging for several reasons, not least because of the problem of controlling the cis/trans selectivity. Surprisingly, in the iridium-catalyzed hydrogenation of 3-substituted benzofurans only one catalyst, based on the cyclohexane-annulated pyridine-phosphinite ligand, showed high activity and enantioselectivity (75-89% conv., 91-92% ee), whereas the five-membered ring analog suffered from moderate activity and enantioselectivity. In contrast, the 2-alkyl substituted benzofurans gave superior results (99% conv., 97-99% ee). Disubstituted thiophene 1,1-dioxides were also investigated in the iridium-catalyzed asymmetric hydrogenation. The hydrogenation of 3,4 disubstituted thiophene 1,1 dioxides using a catalyst based on a cyclopentane-annulated bicyclic pyridine-phosphine ligand gave inferior results to those obtained with their 2,5 disubstituted counterparts.…

Kartoniert / Broschiert. Condición: New. Dieser Artikel ist ein Print on Demand Artikel und wird nach Ihrer Bestellung fuer Sie gedruckt. KlappentextrnrnThe main focus of the research presented in this dissertation was to broaden the substrate scope of the iridium-catalyzed asymmetric hydrogenation of heterocyclic compounds. In view of the fact that a widely applicable hydrogenati.…

Taschenbuch. Condición: Neu. Iridium-Catalyzed Asymmetric Hydrogenation of Furan Derivatives and Thiophene 1,1-Dioxides | Larissa Pauli | Taschenbuch | 178 S. | Englisch | 2014 | Cuvillier | EAN 9783954048519 | Verantwortliche Person für die EU: BoD - Books on Demand, In de Tarpen 42, 22848 Norderstedt, info[at]bod[dot]de | Anbieter: preigu Print on Demand.…

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