Used in peptide synthesis, particularly in the preparation of biologically active peptides containing tryptophan derivatives. The (R)-enantiomer serves as a chiral building block for constructing stereospecific peptide sequences, often applied in research settings for developing enzyme inhibitors or receptor ligands. The Fmoc group allows for solid-phase peptide synthesis using standard Fmoc/t-Bu strategy, enabling mild deprotection conditions. Its indole side chain provides structural similarity to tryptophan, making it useful in designing analogs for structure-activity relationship studies. Commonly employed in pharmaceutical research and development of therapeutic peptides.