Used as a chiral building block in the synthesis of pharmaceuticals, particularly in the development of protease inhibitors and other bioactive molecules. Its stereochemistry allows for selective reactions in asymmetric synthesis, making it valuable in producing enantiomerically pure drugs. Commonly employed in the preparation of intermediates for antiviral and antibacterial agents. The tert-butyl ester group facilitates protection during peptide coupling steps, while the hydrochloride salt enhances stability and handling in solid form.