&Ethyl lactate (I), diethyl a-hydroxymalonate (11), dl-ethyl B-hydroxybutyrate (111), ðyl p- phenyl-@-hydroxypropionate (IV), dimethyl p-hydroxyglutarate (V) and diethyl P- hydroxyglutarate (VI) have been hydrolyzed by a-chymotrypsin. Compounds I, I1 and I11 were hydrolyzed with no stereospecificity, compound I11 hydrolyzing very slowly. Com- pounds IV, V and VI were hydrolyzed stereospecifically, leading to optically pure (-).@. ...