The one-pot MAC (Masked Acyl Cyanide) reaction is used to perform the tandem oxyhomologation reaction of N,N-dibenzyl-l-phenylalaninal and coupling with nitrogen nucleophiles to provide a wide selection of amide and peptide derivatives of (2S,3S)-allophenylnorstatin in generally good yields and with high anti selectivity, often with dr >98:2. The procedure works equally well with other selected N,N-dibenzyl α-amino aldehydes, and is used to achieve a very short synthesis of (2S,3S,S)-epibestatin.