Used primarily in peptide synthesis as a protected amino acid derivative, enabling selective coupling and chain elongation in solid-phase and solution-phase peptide manufacturing. The Fmoc group allows for mild base deprotection, preserving sensitive functional groups. The terminal alkene in the side chain supports post-assembly modifications, such as cross-metathesis or click chemistry, useful in bioconjugation, linker attachment, or functionalizing biomaterials. Commonly employed in developing peptide-based pharmaceuticals, probes, and engineered proteins requiring site-specific modification.