Enzymes in Organic Synthesis, 18. Lipase‐catalyzed Asymmetric Alcoholysis of 3‐Substituted Pentanedioic Anhydrides

Abstract
The influence of several enzymes, alcohols, and solvents on the stereochemical outcome of the asymmetric alcoholysis of 3‐substituted pentanedioic anhydrides was investigated. The alcoholysis of 3‐acetoxypentanedioic anhydride (5a) in diethyl ether with 2‐methylpropanol afforded the (3S)‐monoester (S)‐6a with an enantiomeric excess of > 98% when the lipase from Candida sp. 382 was used as the enzyme. Under the same conditions, 3‐methoxypentanedioic anhydride (5c) was converted by the lipase of Pseudomonas cepacia (Amano PS) into the (3R)‐monoester (R)‐6c with an e.e. of 90%.