Enantioselective oxysulfenylation and oxyselenenylation of olefins catalyzed by chiral Brønsted acids
作者:Huan Guan、Haining Wang、Deshun Huang、Yian Shi
DOI:10.1016/j.tet.2012.01.006
日期:2012.3
This paper describes Brønsted acid catalyzed enantioselective oxysulfenylation and oxyselenenylation of olefins. Enantiomerically enriched tetrahydrofurans are formed with up to 63% ee with dibenzoyl-d-tartaric acid and its derivatives as catalyst. Chiral β-carboxyl sulfides and selenides have also been obtained with up to 50% and 84% ee, respectively, via enantioselective desymmetrization of thiiranium
Enantioselective organocatalytic α-sulfenylation of substituted diketopiperazines
作者:Nathan W. Polaske、Ramin Dubey、Gary S. Nichol、Bogdan Olenyuk
DOI:10.1016/j.tetasy.2009.10.037
日期:2009.12
The asymmetric organocatalytic alpha-sulfenylation of substituted piperazine-2,5-diones is reported, with cinchona alkaloids as chiral Lewis bases and electrophilic sulfur transfer reagents. Catalyst loadings, the type of sulfur transfer reagent, temperature and solvent were investigated in order to optimize the reaction conditions. The effects of ring substitution and the type of catalyst on the yield and enantioselectivity of the reaction are reported. (C) 2009 Elsevier Ltd. All rights reserved.
Efficient organocatalytic α-sulfenylation of substituted piperazine-2,5-diones
作者:Ramin Dubey、Nathan W. Polaske、Gary S. Nichol、Bogdan Olenyuk
DOI:10.1016/j.tetlet.2009.05.031
日期:2009.7
Organocatalytic alpha-sulfenylation of substituted piperazine-2,5-diones is reported through the use of cinchona alkaloids as Lewis bases and electrophilic sulfur transfer reagents. 1-Phenylsulfanyl[1,2,4]triazole, a novel Sulfur transfer reagent, gave excellent product yields with a number of substituted piperazine-2,5-diones under mild conditions. Catalyst loading, stoichiometry Of Sulfur electrophile, temperature, and solvent were optimized to achieve high product yields. (C) 2009 Elsevier Ltd. All rights reserved.
Asymmetric Synthesis of Secondary Alcohols and 1,2-Disubstituted Epoxides via Organocatalytic Sulfenylation
作者:Tom Sheppard、Filippo Rota、Laure Benhamou
DOI:10.1055/s-0035-1560769
日期:——
short reaction sequence involving asymmetricorganocatalytic sulfenylation of an aldehyde, organometallic addition, and desulfurization. This process provides access to enantioenriched alcohols with sterically similar groups attached to the alcohol carbon atom. The intermediate β-hydroxysulfides can also serve as precursors to enantioenriched 1,2-disubstituted epoxides via alkylation of the sulfur and