Fmoc-D-Lys(Boc)-OH is widely used in peptide synthesis as a building block for introducing lysine residues with orthogonal protecting groups. The Fmoc (fluorenylmethyloxycarbonyl) group protects the amino group during solid-phase peptide synthesis, while the Boc (tert-butyloxycarbonyl) group safeguards the side chain amine of lysine. This allows for selective deprotection and functionalization, making it valuable in creating complex peptides with specific modifications. It is particularly useful in synthesizing peptides for drug development, biochemical research, and the study of protein-protein interactions. Its compatibility with automated peptide synthesizers enhances its efficiency in high-throughput applications.