Chelation assistance as a tool for the selective preparation of an imidazole-based mesoionic palladium carbene complex†
Abstract
A C(4)-bound palladium–N-heterocyclic carbene (4) was selectively obtained from the C(2)-unsubstituted imidazolium salt 3. The higher stability of the C(4) versus the C(2)-bound carbene complex due to pyridine chelation assistance allowed this mesoionic compound to be obtained.