Mechanistic Insight into Diaurate-Catalyzed Synthesis of Benzofulvenes through C(sp 3 )–H Activation: A Computational Study

A wide range of gold-catalyzed reactions has continued to increase based on a dual activation mechanism. Herein, the diaurate-catalyzed synthesis mechanism of benzofulvenes through C(sp 3 )–H activation is thoroughly investigated by density functional theory (DFT). A few scenarios are highlighted, including the mode of catalyst transfer, the catalysis mechanism contrast between the Au center and two centers, and the manner of σ-gold coordinated diyne formation. Three mechanistic pathways were computed: (a) a dual-catalysis pathway of precatalyst (pathway a ), (b) a single-catalysis pathway (pathway b ), and (c) a dual-catalysis pathway including 9,8-H transfer (pathway c ). As for the reasonable pathway a, NTf 2 – abstracts a proton from the π-gold complex, generating a σ-coordinated monogold complex. Subsequently, another catalyst coordinates, forming a σ,π-digold complex, which undergoes two consecutive cyclization steps to give non- gem- diaurated species. The reaction subsequently can proceed via three possible routes: ( a 1 ) undergo π-system slippage to yield gem -c, which then undergoes gold transfer and protonation with a substrate to afford benzofulvenes; ( a 2 ) intermolecular protodeauration to generate σ-monoaurated species, followed by protonation with HNTf 2; and ( a 3 ) protonation by HNTf 2 occurs to generate π-monoaurated species, which undergoes intermolecular protodeauration to form benzofulvenes.