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Alloxazine-cyclodextrin conjugates for organocatalytic enantioselective sulfoxidations
- 1.0367200 - ÚOCHB 2012 RIV GB eng J - Journal Article
Mojr, V. - Buděšínský, Miloš - Cibulka, R. - Kraus, Tomáš
Alloxazine-cyclodextrin conjugates for organocatalytic enantioselective sulfoxidations.
Organic & Biomolecular Chemistry. Roč. 9, č. 21 (2011), s. 7318-7326. ISSN 1477-0520. E-ISSN 1477-0539
R&D Projects: GA ČR(CZ) GA203/07/1246; GA ČR GA203/09/1919
Institutional research plan: CEZ:AV0Z40550506
Keywords : cyclodextrins * alloxazines * sulfoxidations
Subject RIV: CC - Organic Chemistry
Impact factor: 3.696, year: 2011
Four structurally different alloxazine–cyclodextrin conjugates were prepared and tested as catalysts for the enantioselective oxidation of prochiral sulfides to sulfoxides by hydrogen peroxide in aqueous solutions. Alpha-cyclodextrin conjugate having alloxazinium unit attached via a short linker proved to be a suitable catalyst for oxidations of n-alkyl methyl sulfides, displaying conversions up to 98% and enantioselectivities up to 77% ee. Beta-cyclodextrin conjugates were optimal catalysts for the oxidation of sulfides carrying bulkier substituents; e.g. tert-butyl methyl sulfide was oxidized with quantitative conversion and 91% ee. Low loadings (0.3–5 mol%) of the catalysts were used.
Permanent Link: http://hdl.handle.net/11104/0201951
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