Enantioselective, Catalytic One‐Pot Synthesis of γ‐Butyrolactone‐Based Fragrances

Abstract

AbstractHerein the preparative (1 g scale), stereoselective syntheses of various alkyl‐substituted γ‐butyrolactone fragrances 1 is described. The α,β‐unsaturated γ‐keto esters 2 as starting materials were synthesized by a Horner‐Wadsworth‐Emmons reaction and are further reduced by an ene reductase and alcohol dehydrogenase in a one‐pot enzyme cascade to nine desired γ‐butyrolactones 1, among them whisky (1 c) and cognac lactone (1 d). The products 1 were obtained in moderate to good yields and very good diastereoselectivities. Furthermore, the position of a nBu‐substituent was permutated to study the effect on the enzyme cascade.