MICROBIOLOGICAL ENANTIOSELECTIVE SYNTHESIS OF (S)-4-(P-ANIXYLOXY)-3-HYDROXYBUTYRATE AND (R)-4-(P-ANISYLOXY)-3-HYDROXYBUTYRATE AS NEW CHIRAL BUILDING-BLOCKS FOR THE SYNTHESIS OF BETA-LACTAM ANTIBIOTICS

Both anantiomers of 4-p-anisyloxy-3-hydroxybutanoates 4 have been prepared in high e.e. by reduction of the corresponding beta-ketoesters or beta-ketocarboxylates with immobilized fermenting baker's yeast. the utility of these new chiral building blocks in the synthesis of pharmacologically important beta-lactam antibiotics has been demonstrated.