Strong Electronic and Counterion Effects on Geminal DigoM Formation and Reactivity as Revealed by Gold(I)-Aryl Model Complexes

摘要

GoId(I) cations have emerged as efficient and often times uniquely effective catalysts for the formation of C-X (X = C, O, N) bonds. Its use as a soft π-acid for the activation of C-C multiple bonds has led to proposed intermediates that include π-gold, Au-vinyl, Au-alkyl, and Au-carbene structures. In many instances a transient Au-C σ-bond is converted into a C-E bond through its reaction with an E~+ electrophile. Recently, we provided evidence that the intramolecular hydroarylation of allenes proceeded through two different gold-vinyl intermediates, one mononuclear (A), and one dinuclear (B), with the latter acting as the catalyst's resting state. The digold structure was proposed to result from the reaction of LAu~+ with monogold-vinyl A Eq. (1).