N-Fmoc-(R)-2-(methylamino)butyric acid is primarily used in peptide synthesis as a protected amino acid derivative. The Fmoc (fluorenylmethyloxycarbonyl) group serves as a protective group for the amine functionality, ensuring selective reactions during the peptide chain assembly process. This compound is particularly valuable in solid-phase peptide synthesis (SPPS), where it enables the controlled and stepwise construction of peptides. Its chiral nature allows for the incorporation of specific stereochemistry into the peptide sequence, which is crucial for achieving the desired biological activity. Additionally, it is employed in the development of peptide-based drugs, biomaterials, and research tools, where precise control over amino acid structure and sequence is essential.