Orthogonally protected Schöllkopf’s bis-lactim ethers for the asymmetric synthesis of α-amino acid derivatives and dipeptide esters

Alkylation of the aza-enolates of orthogonally protected chiral bis-lactim ethers with electrophiles proceeds with good levels of diastereocontrol to afford trans-alkylated adducts that can be efficiently deprotected via hydrolysis/hydrogenation procedures to afford non-proteinogenic α-amino acid or dipeptide ester derivatives.