Convenient Preparation of Copper (I) N-Heterocyclic Carbene Complexes Under Mild Conditions

This work describes a new method for the preparation of copper N-Heterocyclic Carbene (NHC) complexes which is conducted under air with mild conditions, using bench stable precursors and a weak base (NEt3). Under optimized conditions, the complexes were prepared in short reaction times of one hour, giving moderate to good yields after purification by column chromatography. Commonly utilized NHC-HCl salts were found to be applicable reacting with CuCl or CuI giving [(NHC)CuX] type complexes (X = Cl, I). This study adds to the growing literature in the preparation of catalytically relevant transition metal NHC complexes under mild and operationally simple conditions.