α-Alkyl-α-amino esters were prepared by the alkylation of α-imino esters obtained from α-amino acids and a novel PLP modelcompound possessing a Li+ ionophore character.
Synthesis of α,α-dialkyl-α-amino esters by α-alkylation of aldimines prepared from a novel pyridoxalmodelcompound was studied. The α-alkylation of the aldimines having an ethoxy-ethoxy group at C-3 proceeded most rapidly when LiOH was employed as a base and gave α,α-dialkyl-α-amino esters after acidic hydrolysis. The chelated structure composed of the aldimine and Li+ was also revealed by 1H-NMR analysis
Asymmetric α-Alkylation of α-Amino Esters Using Pyridoxal Derivatives Having a Chiral Ansa-Structure and a Chiral Ionophore Function: a Novel Example of Double Asymmetric Induction
Stereoselective alkylation of aldimines, prepared from α-aminoesters and a pyridoxalmodelhaving a chiral ansa-structure and an ethoxyethoxy group at C-3, proceeded in the presence of Li+ to give α,α-dialkyl amino esters after acidic hydrolysis. Double asymmetric induction effect was also observed in the alkylation reaction by combination of the chiral ansa-structure and a chiral ionophore side chain