Used in peptide synthesis as a protected amino acid building block, particularly in the preparation of complex bioactive peptides. The Boc (tert-butoxycarbonyl) group provides temporary protection for the amine functionality, while the benzyl (Bzl) group protects the side-chain hydroxyl, and the N-methylation allows for modulation of peptide conformation and metabolic stability. Commonly employed in solid-phase and solution-phase synthesis of modified peptides, including those with enhanced bioavailability or receptor selectivity. Its D-configuration contributes to resistance against enzymatic degradation, making it valuable in the development of therapeutic peptides and peptidomimetics.