Boc-D-Phe(2-Cl)-OH is widely used in peptide synthesis as a protected amino acid derivative. The Boc (tert-butoxycarbonyl) group serves as a protective group for the amine functionality, preventing unwanted reactions during the peptide chain assembly. The chlorine substituent on the phenyl ring can influence the peptide's biological activity and binding properties, making it valuable in the development of bioactive peptides and pharmaceuticals. It is particularly useful in the synthesis of peptide-based drugs, enzyme inhibitors, and receptor ligands, where specific stereochemistry and functional group modifications are crucial for activity. Additionally, its application extends to research in medicinal chemistry for designing and optimizing peptide structures with enhanced stability and specificity.