Widely used in peptide synthesis, this compound serves as a protected amino acid building block, particularly in the preparation of constrained cyclic peptides. The Fmoc group allows for mild base-labile protection of the amine, enabling solid-phase peptide synthesis (SPPS) under standard conditions. Its cyclobutane backbone introduces conformational rigidity, which is valuable for studying structure-activity relationships in bioactive peptides. It is especially useful in medicinal chemistry for designing peptidomimetics with enhanced metabolic stability and receptor selectivity.