Used as a chiral building block in the synthesis of pharmaceuticals and peptides, particularly in the development of protease inhibitors and antiviral agents. Its benzyl ester group acts as a protecting group for the carboxylic acid function of serine, allowing selective reactions at other functional sites during peptide coupling. The hydrochloride salt form enhances stability and solubility in polar solvents, making it suitable for solid-phase and solution-phase peptide synthesis. Also employed in the preparation of enzyme substrates and analogs for biochemical studies.