Perfluoroalkyl Analogues of Diethylaminosulfur Trifluoride: Reagents for Perfluoroalkylthiolation of Active Methylene Compounds under Mild Conditions.

Trifluoromethyl diethylaminosulfur difluoride (CF3-DAST) was found to be an efficient reagent for the trifluoromethylthiolation of α-methylene-β-keto esters providing α-trifluoromethylthio-β-keto esters in good to high yields. α-Methylene-β-keto sulfones were also accepted as substrates by CF3-DAST to furnish the corresponding α-trifluoromethylthio compounds. This strategy can be extended to perfluoroalkylthiolation reactions using perfluoroethyl-DAST (C2F5-DAST) and perfluoropropyl-DAST (C3F7-DAST).