Amino-functionalized imidazolium salts as modular precursors for the synthesis of N-heterocyclic carbene complexes

Increasing attention has been addressed on using N-heterocyclic carbenes (NHCs) as ancillary ligands for a number of metal catalytic reactions. Our attention has been focused on NHC-amino metal complexes whose chelating and anchoring abilities have been scarcely employed in catalysis so far. We herein describe a new , selective synthesis of the 1-(2’-NHBoc-ethyl-)-3-methylimidazolium iodide (1) and its use as precursor for the synthesis of NHC metal complexes. Reaction of imidazolium salt (1) with Ag2O allows the straightforward formation of silver complexes employed as transmetallating agents for the formation of Rhodium- and Palladium-NHC complexes.