Used in peptide synthesis as a protected amino acid building block, particularly in the preparation of modified peptides for pharmaceutical and biochemical research. The Fmoc group allows for mild, base-labile protection compatible with solid-phase synthesis, enabling stepwise assembly of complex peptide sequences. The 3-cyanophenyl substituent introduces structural diversity and can influence peptide conformation or binding properties, making it valuable in the design of bioactive peptides and peptidomimetics. Commonly applied in the development of enzyme inhibitors, receptor ligands, and probes for studying biological systems.