Synthesis of N-protected Non-proteinogenic α-amino Acid Esters by Using Trichloroacetimidate and Acetate Coupling Methods

A series of N-protected non-proteinogenic α-amino acid esters have been prepared. The key step in this synthesis is the treatment of trichloroacetimidate 3, 8 or acetate 4, 9 derivatives with Lewis acid and C-active nucleophiles to afford the desired products via C-C bond formation and the introduction of substituents at the α-position of the amino acid in good yields and short reaction time.