Selective Synthesis of Perfluoroalkyl-Containing Thioamides and Thioamide S-Oxides by the Reaction of Perfluoroalkyl Sulfoxides and Secondary Amines.

A novel method for the selective synthesis of perfluoroalkylated thioamides and thioamide S-oxides has been developed through the reaction of perfluoroalkyl sulfoxides with secondary amines. The selectivity of the reaction can be easily modulated by employing different additives. Specifically, PCl3 promotes the formation of thioamides, whereas ZnCl2 facilitates the formation of thioamide S-oxides. This protocol tolerates a broad range of substrates, including aromatic, aliphatic, and cyclic secondary amines, as well as sulfoxides containing different perfluoroalkyl groups. The plausible mechanistic pathways were proposed on the basis of experimental results.