Enantiopure α-Difluoromethyl Amines from N-(tert-Butylsulfinyl)aldimines

Significance

Nucleophilic addition of (phenylsulfonyl)difluoromethyl anion (PhSO₂CF₂-) to N-(tert-butylsulfinyl)aldimines resulted in N-tert-butylsulfinyl-protected amines in good to excellent yields and excellent diastereoselectivity. A broad range of substrates were tolerated under the reaction conditions including aryl, hetereoaryl, and alkyl­aldimine bearing an α-hydrogen. Simultaneous removal of the tert-butylsulfinyl and phenylsulfonyl groups under reductive conditions (Na/Hg) gave the desired α-difluoromethyl amines, which were isolated as their HCl salts. This process conveniently produced a variety of enantiopure α-difluoromethyl amines from readily accessible starting materials.