Fmoc-D-Nle-OH is widely used in peptide synthesis, particularly in solid-phase peptide synthesis (SPPS). It serves as a building block for introducing the non-natural amino acid D-norleucine into peptide chains. The Fmoc (9-fluorenylmethoxycarbonyl) group acts as a protecting group for the amine functionality, ensuring selective coupling during peptide assembly. This compound is valuable in creating peptides with specific structural and functional properties, often employed in drug development, biochemical research, and the study of peptide-protein interactions. Its use allows for the precise incorporation of D-norleucine, which can enhance peptide stability, alter biological activity, or serve as a probe in mechanistic studies.