(2-Bromoethyl)sulfonium Trifluoromethanesulfonates in Stereoselective Annulation Reactions for the Formation of Fused Bicyclic Epoxides and Aziridines

摘要

A versatile and simple methodis reported for the synthesis of bicyclic epoxide and aziridine?￡?fused heterocycles (up to 98% yield, up to 96: 4 er or up to 15: 1 dr), using a tandem Michael addition/ Johnson?￡?Corey?￡?Chaykovsky annulation approach. A new chiral (2-bromoethyl)sulfonium reagent is described, based on an easily available chiral sulfide; it promotes or enhances stereoselectivity in the reaction.