Enantioselective Synthesis of Benzothiazolines from Fluoroalkyl Ketones Using Chiral Imidazoline−Phosphoric Acid Catalysts

Abstract

The first enantioselective synthesis of cyclic N,S-ketals having tetrasubstituted chiral center through intramolecular cyclization between carbonyl compounds and aminothiols has been developed. The reaction of fluoroalkyl ketones with aminobenzenethiols using a chiral imidazolineÀ phosphoric acid catalyst afforded products in high yields with high enantioselectivity. The observed enantioselectivity is explained using preliminary mechanistic information.