A new steroselective route to .GAMMA.-butyrolactones: asymmetric syntheses of (+)-trans-whisky and (+)-trans-cognac lactones.

Abstract

A new stereoselective route to γ-butyrolactones such as (+)-trans-whisky and (+)-trans-cognac lactones (1a, b) has been developed by a combination of three key reactions : diastereoselective nucleophilic addition of thiophenol, cleavage of chiral N-acylsultam via thioester, and intramolecular displacement of the sulfonium group with carboxylate anion.