ChemInform Abstract: Chiral N‐Heterocyclic Carbene Ligands Bearing a Pyridine Moiety for the Copper‐Catalyzed Alkylation of N‐Sulfonylimines with Dialkylzinc Reagents.

Abstract

Amino acid-derived chiral imidazolium salts, each bearing a pyridine ring, are developed as N-heterocyclic carbene ligands. The copper-catalyzed asymmetric alkylation of various N-sulfonylimines with dialkylzinc reagents in the presence of these chiral imidazolium salts affords the corresponding alkylated products with high enantioselectivity. The addition of HMPA to the reaction mixture as a co-solvent is critical in terms of chemical yield and enantioselectivity. A wide range of N-sulfonylimines and dialkylzinc reagents is found to be applicable to this reaction. -(SOETA, T.; ISHIZAKA, T.; TABATAKE, Y.; UKAJI*, Y.; Chem. -Eur.