Reactivity of NHC Au(i)-C σ-bonds with electrophiles. An investigation of their possible involvement in catalytic C-C bond formationElectronic supplementary information (ESI) available, including experimental and computational details, X-ray data and NMR spectra for all new compounds. CCDC reference numbers 832959-832962. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c1sc00428j

The first example of the reaction of an isolated gold( i ) complex with an aryl halide to form a C-C bond is reported. The reactivity of (NHC)Au( i )-R complexes towards a wide range of electrophiles was investigated. The Au-C σ-bond is shown to exhibit low nucleophilicity, but it is reactive towards MeI and MeOTf to form toluene, biphenyl and ethane, most likely through an oxidative mechanism. Carbon dioxide is completely unreactive. The experimental findings are supported by theoretical calculations. An (NHC)Au-Ph complex reacts with aryliodides to give the corresponding cross-coupled product, whereas the weaker electrophile CO 2 is unreactive.