Unexpected ring expansion of an enantiopure imidazoline carbene ligand

[GRAPHICS] We report an unexpected ring expansion reaction of an enantiopure fenchone-derived imidazolinium salt during attempts to form copper complexes of the corresponding imidazoline carbene ligand. A N, N'-difenchyl piperazinone was formed in low yield together with the difenchyl-substituted five-membered urea.