N-Heterocyclic Carbene Ligands in Copper-Catalyzed Addition of Diethylzinc to N-Sulfonylimines

Abstract

N-Heterocyclic carbenes (NHCs) were generated in-situ from imidazolium and imidazolinium salts by deprotonation of C-2 hydrogen and were used as ligands in the copper-catalyzed addition of diethylzinc to N-sulfonylimines. The copper–NHC complexes were shown to possess an efficient ligand acceleration effect (LAE).