ENZYMES IN ORGANIC-SYNTHESIS .18. LIPASE-CATALYZED ASYMMETRIC ALCOHOLYSIS OF 3-SUBSTITUTED PENTANEDIOIC ANHYDRIDES

The influence of several enzymes, alcohols, and solvents on the stereo chemical outcome of the asymmetric alcoholysis of 3-substituted pentan edioic anhydrides was investigated. The alcoholysis of 3-acetoxypentan edioic 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 co nditions, 3-methoxypentanedioic anhydride (5c) was converted by the li pase of Pseudomonas cepacia (Amano PS) into the (3R)-monoester (R)-6c with an e.e. of 90%.