Diastereoselective synthesis of CF3-substituted, epoxide-fused heterocycles with β-(trifluoromethyl)vinylsulfonium salts.

CF(3)-substituted vinyl diphenylsulfonium triflate is an effective annulation reagent for the formation of α-CF(3) substituted, epoxide-fused heterocycles (pyrrolidines, piperidines, and tetrahydrofurans). This simple method affords a variety of valuable heterocyclic building blocks in a highly diastereoselective manner (dr >20:1).