Cooperative Dinuclear Gold Catalysis Unlocking 1,2-Reductive Elimination Elementary Reaction in Oxidative C-C Coupling

Abstract

Cooperative catalysis enabled by dinuclear metal complexes can integrate the catalytic properties of each metal center, thus opening new avenues to achieve challenging reaction selectivity that are difficult to accomplish with mononuclear metal catalysts. Herein, we present a cooperative catalysis strategy using a newly synthesized dinuclear PNP-Au2 catalyst, which positions two gold centers in close proximity, facilitating favorable geometric and electronic interactions for the synergistic activation of both coupling partners (alkynes and vinyl boron reagent) in oxidative C-C coupling. It demonstrates a broad substrate tolerance for both terminal and internal alkynes, providing a versatile platform for the synthesis of enynes and dienes. Mechanistic and computational studies reveal a unique 1,2-cooperative activation mode, significantly reducing the free energy barrier and stabilizes key intermediates, thus promoting C-C bond forming in an efficient manner. The DFT calculation indicates a less explored 1,2-reductive elimination elementary step. Interestingly, the use of B(OiPr)3 as additive would successfully prevent dinuclear gold catalyst decomposition under oxidative conditions in the presence of fluoride.