Synthesis, Characterization, and Catalytic Activity of Alcohol-Functionalized NHC Gold(I/III) Complexes

A series of alcohol-functionalized NHC gold­(I/III) complexes of the types [(L)­Au­(Cl or NTf2)] and [(L)­AuCl3] (L = IPrEtOH, (1, 4, 5), IMesEtOH (2, 6), IMeEtOH (3, 7)) was readily synthesized and characterized by NMR spectroscopy and single-crystal X-ray diffraction. The catalytic activity of the new complexes was assessed and compared with that of other gold catalysts, in the tandem 3,3-rearrangement–Nazarov reactions of enynyl acetate and the rearrangement reaction of alkynyloxirane. The new complexes appeared to be dual-site catalysts in both transformations, thanks to the presence of the primary alcohol function tethered to the NHC ligands.