A Highly Efficient Method for Synthesis of Fmoc-Lysine(Mmt)-OH
N α-9-Fluorenylmethoxycarbonyl-N ε-4-methoxy trityl-ly sine [Fmoc-Lys(Mmt)-OH], an extremely acid labile derivative of lysine, was previously reported by Matyslak . Because the N ε-Mmt moiety of lysine is extremely acid labile, the first attempt to synthesize it failed . Compared to Mtt group, the Mmt moiety of lysine can be effectively cleaved by DCM/TFE/AcOH (7:2:1), even if the compound is coupled to hydrophilic Tentagel and PEG resins. For the preparation of branched and cyclic peptides or the modification of peptides with dye labels, biotin, or many particular functional groups, Fmoc-Lys(Mmt)-OH is a useful building block. In this report, we describe a highly efficient method for synthesis of Fmoc-Lys(Mmt)-OH.