Fmoc-lys (BOC) (ME)-OH is a kind of protected form of lysine. Lysine is double-protected by butyloxycarbonyl (BOC) and 9H-fluoren-9-ylmethoxycarbon (FMOC). It is a derivative for the introduction of monomethyl-lysine during Fmoc SPPS. Coupling can be carried out using any standard activation method. The Boc protecting group can be removed through the TFA-mediated cleavage reaction. As a kind of protected amino acid, it is an important intermediate in various fields such as peptide synthesis, asymmetric synthesis, medicinal chemistry as well as polymer chemistry.