Synthesis of highly enantiomerically enriched N-Boc-α-amino ketones from pseudoephedrine N-Boc-α-amino acid amides

N-Boc-α-amino ketones are synthesized efficiently and in high enantiomeric excess by the addition of organolithium and Grignard reagents to pseudoephedrine amides of N-Boc-α-amino acids, themselves available by the alkylation of pseudoephedrine glycinamide followed by N- protection.