Organocatalytic enantioselective α-difluoromethylketone thiolation of β-keto esters using phthalimide-SCF2COAr

Abstract

The first asymmetric α-difluoromethylketone thiolation of diverse β-keto esters using an electrophilic phthalimide-SCF₂COAr reagent (PhthN-SCF₂COAr) was reported. In the presence of cinchona-alkaloid-based catalyst (DHQD)₂PHAL, the reaction was achieved in moderate yields with a moderate to excellent enantioselectivity (up to 93% ee) under mild reaction conditions and exhibited functional group compatibility. An ammonium hydrogen-bonded induction model was proposed to rationalize the origin of enantioselectivity.