Activation of C–F bonds in fluoroarenes by N-heterocyclic carbenes as an effective route to synthesize abnormal NHC complexes

Abstract

IPr (1a) reacts with octafluorotoluene by an unexpected sequential substitution of fluorides in two separate rings. The resulting tetrasubstituted imidazolium salt was isolated and elaborated into Ag(I) and Au(I) complexes with a novel abnormal NHC ligand. Both IPr (1a) and IMes (1b) were also found to be moderately reactive by nucleophilic substitution of the aromatic C–F bond in a weakly-activated fluoroarene, 1-fluoro-4-trifluoromethylbenzene (5).