Boc-N-methyl-L-isoleucine (dicyclohexylammonium) salt is primarily used in peptide synthesis. It serves as a protected amino acid derivative, where the Boc (tert-butyloxycarbonyl) group safeguards the amino functionality during the synthesis process. This protection is crucial to prevent unwanted side reactions and to ensure the correct sequence of amino acids in the final peptide product.

The dicyclohexylammonium salt form enhances the compound's solubility in organic solvents, making it more suitable for use in non-aqueous reaction environments commonly employed in peptide synthesis. This compound is particularly valuable in the synthesis of complex peptides and proteins, where precise control over the incorporation of amino acids is essential.

Additionally, it finds application in the development of pharmaceuticals, especially in the production of peptide-based drugs. The N-methylation of the isoleucine residue can influence the peptide's biological activity, stability, and resistance to enzymatic degradation, making it a critical component in the design of therapeutic peptides.