A concise synthesis of ( S)-(+)-5,6-2 H-pyran-2-one via hydrozirconation–carbonylation–demetallation of O-benzyl ( S)-(−)-4-pentyn-2-ol

Abstract

A simple synthetic approach to α,β-unsaturated δ-lactones has been devised from the hydrozirconation of O-protected homopropargyl alcohols followed by carbonylation and quenching with iodine. The synthesis of ( S)-(+)-5,6-2 H-pyran-2-one (parasorbic acid) from easily available O-benzylated ( S)-(−)-4-pentyn-2-ol was chosen to exemplify the approach.