Asymmetric α-alkylation of α-amino esters using pyridoxal model compounds with a chiral ionophore function; dependence of stereoselectivity on a chelated metal ion
摘要:
Asymmetric alpha-alkylation of alpha-amino esters by use of novel pyridoxal model compounds having a chiral ionophore function is studied; the stereoselectivity is specifically induced by Na+ and the most effective asymmetric induction occurs with a combination of Na+ and an additional chiral ansa-structure.
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