Boc-D-Phenylglycine is a protected amino acid derivative, specifically the tert-butoxycarbonyl (Boc) protected form of D-phenylglycine. It is a white to off-white crystalline powder. The Boc group serves as a crucial amine-protecting group in peptide synthesis, allowing for selective deprotection under mild acidic conditions without affecting other sensitive functional groups. This compound is a key chiral building block in the pharmaceutical industry. Its primary application is as an intermediate in the synthesis of various active pharmaceutical ingredients (APIs), particularly β-lactam antibiotics. D-Phenylglycine and its derivatives are essential side-chain components in semisynthetic penicillins and cephalosporins, such as ampicillin and cephalexin, contributing to their antibacterial activity and pharmacokinetic properties. As a Boc-protected amino acid, it is widely used in solid-phase peptide synthesis (SPPS) and solution-phase peptide chemistry to introduce the D-phenylglycine residue into peptide sequences. Its high chiral purity is critical for ensuring the biological activity of the final peptide or drug molecule.