Used in solid-phase peptide synthesis as a chiral building block for incorporating propargylglycine derivatives into peptides. The Fmoc group allows for mild base-labile protection of the alpha-amine, compatible with orthogonal protection strategies in Fmoc/tBu synthesis. The terminal alkyne moiety enables site-specific post-assembly modifications via click chemistry, such as copper-catalyzed azide-alkyne cycloaddition (CuAAC), useful in bioconjugation, fluorescent labeling, and peptide-protein crosslinking. Commonly applied in the development of peptide-based drugs, probes, and biomaterials where precise functionalization is required.