LIPASE-CATALYZED PREPARATION OF OPTICALLY-ACTIVE GAMMA-BUTYROLACTONES IN ORGANIC-SOLVENTS

Lipases in anhydrous organic solvents catalyze the lactonization of esters of 7-hydroxy carboxylic acids with a high degree of stereospecificity. Under these conditions the lipases exhibit both enantioselectivity and prochiral selectivity. We exploited the enzymes’ enantioselectivity for synthesis of chiral lactones from racemic 7-hydroxy esters and their prochiral stereospecificity, i.e. the ability to discriminate between enantiotopic groups of a prochiral molecule, for the enantioconvergent lactonization of symmetrical 7-hydroxy diesters. This approach was used to develop a convenient, high-yielding, and stereoselective route to several optically active 7-substituted λ-bu-tyrolactones. © 1990, American Chemical Society. All rights reserved.