Regio- and stereoselective α-alkylation of N-terminal amino acid residue of peptides using a pyridoxal model compound with a chiral ansa-structure

Regio- and stereoselective α-alkylation of N-terminal amino acid residue of peptides was achieved by Li+-mediated alkylation of aldimines prepared from the peptides and a pyridoxal model compound having a chiral ansa-structure and an ethoxyethoxy group at C-3. The stereochemistry and stereoselectivity of the reaction were found to be influenced predominantly by the chirality of the model compound and Li+, but little by the stereochemistry of the original peptides.