High anti Diastereoselectivity in a Tandem Oxyhomologation-Coupling Protocol for the Preparation of Amides and Peptides Incorporating α-Hydroxy β-Amino Acids.

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 (2 S ,3 S )-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 (2 S, 3 S,S )-epibestatin.