Copper(I) Complexes of Phenanthro‐Annulated N‐Heterocyclic Carbenes: Synthesis and Transmetalation Reactions

Copper(I) complexes with phenanthro-annulated N-heterocyclic carbene ligands were prepared by reaction of imidazolium salts with copper(I) oxide. Transmetalation of the copper complexes with [RhCl(cod)]2 in usual solvents like CH2Cl2 led to an equilibrium between the reactants and the products. For rhodium complexes 4 and 5 this equilibrium could be shifted to the product side by carrying out the reaction in acetonitrile. The ester functionalized rhodium complex 6 was prepared in a two phase mixture of chloroform and aqueous CaCl2 starting from copper complex 3c. The rhodium complexes were characterized by NMR and X-ray measurements.