Palladium-Catalyzed Tandem Synthesis of 2-Trifluoromethylthio(seleno)-Substituted Benzofused Heterocycles.

The tandem synthesis of 2-trifluoromethylthio(seleno)-substituted benzofurans using palladium-catalyzed conditions is reported. Trifluoromethylthio(seleno)lation of 2-(2,2-dibromovinyl)phenols with (bpy)CuSCF or [(bpy)CuSeCF] furnishes several 2-trifluoromethylthio(seleno)lated benzofurans in acceptable to good yield. Mechanistic investigations were performed to elucidate the reaction pathway, which was involved in the formation of a 2-bromobenzofuran species. The scope of this protocol was further extended to the preparation of 2-trifluoromethylthio(seleno)lated benzothiophenes and indoles.