Used in peptide synthesis, particularly in solid-phase peptide synthesis (SPPS), to introduce chloro-substituted phenylalanine residues into peptide chains. The Fmoc group serves as a protective group for the amino acid, ensuring selective reactions during peptide assembly. Its chloro substitution can enhance the peptide's stability, binding affinity, or biological activity, making it valuable in drug development and biochemical research. Commonly applied in the production of therapeutic peptides, enzyme inhibitors, and probes for studying protein interactions.