Used as an intermediate in the synthesis of β-lactam antibiotics, particularly in the preparation of penem and carbapenem classes. Its structure contains a reactive azetidinone ring that enables ring expansion and side chain modifications essential for enhancing antibiotic activity and resistance to β-lactamases. The (S)-configuration ensures proper stereochemistry crucial for the biological activity of the final products. Commonly employed in pharmaceutical research to develop broad-spectrum antibiotics with improved stability and potency.