Enzyme-Mediated Synthesis of (S)- and (R)-Verapamil

Abstract

A lipase-mediated synthesis of (S)- and (R)-verapamil is described. The key steps of the synthetic sequence are the enantioselective acetylation, mediated by Lipase PS, of allylic alcohol (Z)-(±)-2, affording the acetate derivative (Z,R)-(−)-3 (ee 92%) and the Ireland−Claisen rearrangement of this latter and of its enantiomer (Z,S)-(+)-3 (ee 92%) to afford acid derivatives (E,R)-(−)-4 (ee 94%) and (E,S)-(+)-4 (ee 93%), precursors of (S)- and (R)-verapamil, respectively.