Chiral non-racemic sulfoxides by asymmetric alkylation of alkanesulfenates in the presence of a chiral ammonium phase-transfer catalyst derived from <i>Cinchona</i> alkaloid
作者:Fabien Gelat、Annie-Claude Gaumont、Stéphane Perrio
DOI:10.1080/17415993.2013.795226
日期:2013.12.1
Based on a previous study involving arenesulfenates, the enantioselective S-alkylation of benzyl and alkyl sulfenates (RSO-)-S-1 wth alkyl halides, mediated by a cinchonidinium phase-transfer catalyst, was evaluated as a conceptually different synthetic approach to chiral sulfoxides. Direct application of our standard organocatalytic protocol, with methyl iodide as the electrophile, was rather disappointing mainly as a result of a sluggish release of the sulfur nucleophiles. However, slight modifications of the reaction conditions allowed the isolation of (R)-benzyl methyl sulfoxide in a 60% yield and a 38% ee, whereas (R)-cyclohexyl methyl sulfoxide was produced in a 34% yield and a 47% ee.[GRAPHICS].