IBiox[(-)-menthyl]: A Sterically Demanding Chiral NHC Ligand

An exceedingly sterically demanding, rigid, and chiral NHC ligand, IBiox[(-)-menthyl] (1), was prepared and structurally characterized. With a buried volume of similar to 50%, this ligand arguably represents one of the most sterically demanding monodentate ligands. The ability to use aryl chloride substrates in intramolecular palladium-catalyzed alpha-arylations reveals its unique reactivity. Moreover, C-2-symmetric 1 allows the highly enantioselective formation of oxindoles with up to 99% ee.