Used in peptide synthesis as a chiral building block for incorporating phenylalkyl side chains with defined stereochemistry. The Fmoc group allows for solid-phase synthesis by providing orthogonal protection of the amino group, enabling stepwise assembly of peptides. The carboxylic acid functionality can be activated for amide bond formation with amino acids or resins. Its (R)-configuration is valuable for studying stereochemical effects in bioactive peptides or designing enzyme inhibitors where side chain orientation impacts activity. Commonly applied in medicinal chemistry for developing peptidomimetics and structurally modified peptides with enhanced stability or receptor selectivity.