Used as an intermediate in the synthesis of peptides and pharmaceuticals, particularly in protecting the serine amino acid during peptide bond formation. Its benzyl ester group helps prevent unwanted side reactions at the carboxyl end, while the benzenesulfonate salt enhances stability and crystallinity, making it easier to handle and purify in multi-step organic syntheses. Commonly applied in the production of antibiotics and other bioactive molecules where precise amino acid sequencing is critical.