Racemic fluoroalkyl (E) -vinyl carbinols (1a-d) were kinetically resolved by Sharpless epoxidation. The optical purity of the resolved alcohols was excellent (98% ee) in mono-and difluoromethyl derivatives (1b and 1c) and moderate (60% ee) in a trifluoromethyl compound (1a).
Fluoroalkyl alkynyl ketones (1a-c) were reduced enantioselectively by (R) -BINAL-H and (S) -Alpine-Borane to give optically active alcohols (2a-c). In the BINAL-H reduction, the trifluoromethyl group exerted an electronic effect on the enantioselectivity of the reagent.