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.