(S)-tyrosine benzyl ester is primarily used in peptide synthesis as a building block for creating complex peptides and proteins. It serves as a protected form of tyrosine, where the benzyl ester group safeguards the carboxyl functionality during the synthesis process. This protection is crucial to prevent unwanted reactions and ensure the correct sequence of amino acids in the final peptide product. Additionally, it is employed in the development of pharmaceuticals, particularly in the design of drugs targeting neurological disorders, as tyrosine derivatives play a role in neurotransmitter synthesis. Its chiral nature also makes it valuable in asymmetric synthesis for producing enantiomerically pure compounds, which are essential in drug development to avoid side effects and enhance efficacy.