Mono-N-ethylated alpha-amino acid esters are obtained in high yields using reductive amination procedures. Formation of imine is achieved by excess of acetaldehyde, followed by removal of acetaldehyde and reduction by NaBH(OAc)(3). The elaborated one-pot synthesis allows for the efficient synthesis of side-chain protected amino acid derivatives. Copyright (C) 1999 European Peptide Society and John Wiley & Sons, Ltd.