Boc-3,5-Dichloro-D-Phenylalanine is a non-natural, Boc-protected derivative of D-phenylalanine with chlorine substituents at the 3 and 5 positions of the phenyl ring. This compound is a chiral building block characterized by its high optical purity, which is crucial for the synthesis of enantiomerically pure pharmaceuticals and bioactive peptides. Its primary application is as a key chiral intermediate in medicinal chemistry and drug discovery. The presence of the electron-withdrawing chlorine atoms and the D-configuration makes it a valuable precursor for constructing peptide-based drug candidates, protease inhibitors, and other biologically active molecules where specific stereochemistry and modified aromatic side chains are required to modulate binding affinity, metabolic stability, or physicochemical properties. The tert-butoxycarbonyl (Boc) protecting group on the amino function allows for orthogonal deprotection strategies under mild acidic conditions, facilitating its use in solid-phase peptide synthesis (SPPS) and solution-phase fragment coupling. This reagent is typically handled under inert atmosphere and stored at low temperatures to ensure stability.