Used in peptide synthesis as a protected amino acid derivative, particularly in the preparation of enzyme inhibitors and pharmaceutical intermediates. The Fmoc group allows for solid-phase synthesis by providing temporary N-terminal protection that is base-labile and compatible with a wide range of side-chain protecting groups. The cyclopentyl side chain imparts structural similarity to certain natural amino acids, making this compound useful in the design of protease inhibitors, especially for targets like HCV NS3 protease. Commonly employed in medicinal chemistry for developing bioactive peptides with enhanced metabolic stability and receptor selectivity.