Microbiological Enantioselective Synthesis of (S) and (R) 4-(p-Anisyloxy)-3-hydroxybutyrates as New Chiral Building Blocks for the Synthesis of b-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.