Flash Communication: Challenging Computational Description of Gold(I)/Gold(III) Catalytic Cycles

We have investigated the mechanism of cross-coupling reactions catalyzed by gold(I) complexes without the assistance of chelating ligands. Following pioneering studies by Kochi, gold(I) complexes with simple alkyl phosphines as ligands are considered. The reaction between cinnamyl bromide and PhSnMe3 is experimentally shown to take place in the presence of a [Me3PAuCl] complex. However, our attempt to characterize computationally, using density functional theory (DFT), a mechanism following a plausible gold(I)/gold(III) catalytic cycle unearths an unexpectedly complex situation, showing a large range of energy values computed with different functionals.