Used in peptide synthesis as a protected amino acid building block, particularly in solid-phase peptide synthesis (SPPS). The Fmoc group provides temporary protection for the amine functionality, allowing selective coupling reactions, while the cyclopropylglycine moiety introduces a conformationally constrained amino acid residue that can enhance peptide stability and influence biological activity. Commonly employed in the development of pharmaceuticals and bioactive peptides where structural rigidity is desired. Its use supports stepwise assembly of complex peptides with high purity and yield under mild basic conditions.