Used in solid-phase peptide synthesis to introduce a modified amino acid residue with a pentynyl side chain, enabling site-specific conjugation via click chemistry. The Fmoc group allows for mild deprotection conditions, preserving the integrity of the alkyne functionality. This makes it valuable in the synthesis of peptide-based probes, bioconjugates, and functional biomaterials where precise labeling or crosslinking is required. Commonly applied in pharmaceutical research and chemical biology for developing peptide-drug conjugates and diagnostic tools.