Used as a chiral building block in the synthesis of pharmaceuticals, particularly in the development of protease inhibitors and other bioactive molecules. The hydrochloride salt form of the amine group and the tert-butyl ester protected carboxylic acid groups allow selective reactions in peptide-like structures. The tert-butyl ester groups offer stability under various reaction conditions and can be deprotected under mild acidic conditions, making it suitable for multi-step organic syntheses. Commonly employed in asymmetric synthesis to introduce stereochemistry in drug candidates.