Orthogonally Protected Schoellkopf′s Bis-Lactim Ethers for the Asymmetric Synthesis of α-Amino Acid Derivatives and Dipeptide Esters.

A diastereoselective trans-alkylation of aza-enolates of orthogonally protected chiral bis-lactim ethers with electrophiles, such as alkyl halides, and subsequent deprotection via hydrolysis/hydrogenation leads to dipeptide ester derivatives.