A general route to «carba» peptide bond replacements : unequivocal synthesis of BOC-2L-PHE-ψ(CH2-CH2)-2D-ALA-OH

An unambiguous synthesis of title compounds from Boc-L-phenylalanine, through lactame intermediates (3R,6R)-3-methyl 6-benzyl-piperidin-2-one and (3S,6R)-3-methyl 6-benzyl-piperidin-2-one, is described