Enantioselective Cobalt-Catalyzed Hydroboration of Fluoroalkyl-Substituted Alkenes to Access Chiral Fluoroalkylboronates.

Abstract

Selective defluoroborylation and asymmetric hydroboration reactions of fluoroalkyl-substituted terminal alkenes with pinacolborane (HBpin) have been developed with cobalt catalysts generated from Co(acac)2 and bisphosphine ligands. A variety of fluoroalkyl-substituted terminal alkenes undergo this enantioselective hydroboration, affording the corresponding chiral alkylboronates containing fluoroalkyl-substituted stereogenic carbon centers with high enantioselectivity (up to 98% ee). This asymmetric hydroboration provides a versatile foundation for the synthesis of a variety of chiral organofluorine compounds containing fluoroalkyl-substituted stereogenic carbon centers.