N-[(2-Methyl-2-propanyl)oxy]carbonyl-3-(methylsulfonyl)-L-valine is a specialty protected amino acid derivative used primarily in peptide synthesis. The tert-butoxycarbonyl (Boc) group protects the α-amino group of the 3-(methylsulfonyl)-L-valine, enabling selective activation and coupling of the carboxylic acid during solid-phase or solution-phase peptide assembly. This ensures precise control over the incorporation of the modified valine residue into peptide chains. The methylsulfonyl (mesyl) substituent at the β-position enhances the compound's solubility in organic solvents and provides improved stability under various reaction conditions. It is particularly valuable in the synthesis of modified peptides, peptidomimetics, and peptide-based pharmaceuticals for drug discovery and biochemical research.