Used as a chiral building block in the synthesis of pharmaceuticals, particularly in the development of active pharmaceutical ingredients (APIs) requiring high enantiomeric purity. Its protected amine and carboxylic acid functionalities make it suitable for peptide-like coupling reactions and heterocyclic modifications. Commonly employed in the preparation of protease inhibitors and other bioactive molecules where the (S)-configuration is critical for biological activity. The tert-butoxycarbonyl (Boc) group allows for easy deprotection under mild acidic conditions, enabling further functionalization in multi-step organic syntheses.