Used as a chiral building block in the synthesis of peptide-based pharmaceuticals. Its protected functional groups allow selective deprotection and coupling in solid-phase or solution-phase peptide synthesis. The allyl and tert-butoxycarbonyl (Boc) protecting groups provide orthogonal stability, enabling stepwise assembly of complex peptides with controlled stereochemistry. Commonly employed in the preparation of enzyme inhibitors and bioactive peptides where stereochemical purity is critical.