Enzymes in Organic Synthesis. 39. Preparations of Chiral Cyclic Acid-Esters and Bicyclic Lactones via Stereoselective Pig Liver Esterase Catalyzed Hydrolyses of Cyclic Meso Diesters

Article abstract of DOI:10.1021/jo00229a024

Pig liver esterase catalyzed hydrolyses of meso-dimethyl cyclopropane-, cyclobutane-, and cyclohexane-1,2-dicarboxylates are enantiotopically specific, giving acid-ester products that are readily converted into γ-lactones of > 97percent ee that are of value as chiral synthons.There is a dramatic change of stereospecificity on going from the cyclopropane and cyclobutane diesters to the cyclohexane substrate, with the cyclopentane diester hydrolysis representing the changeover point within the series.This reversal of enzyme stereospecificity is explicable in terms of a twobinding-pocket active-site model.Hydrolyses of dimethyl oxirane-2,3-dicarboxylate and of cyclopropane-1,2-diacetates are also stereoselective, giving product ee's up to 30-70percent.