Theoretical investigation of gold-catalyzed oxidative Csp3–Csp2 bond formation via aromatic C–H activation

Abstract

The mechanisms of Selectfluor-mediated Au-catalyzed intramolecular C_sp3–C_sp2 cross-coupling reaction involving direct aryl C_sp2–H functionalization have been investigated theoretically. Several pathways involving the oxidation of alkylgold(I) (Cycle I), phosphine Au(I) precatalyst (Cycle II), gold(I) π–alkene complex (Cycle III) and arylgold(I) (Cycle IV) by Selectfluor, respectively, were examined. Our calculation results suggested the following: (1) Cycles I and II are preferred over Cycles III and IV, and the reaction would undergo the energy favored pathways (Cycles I and II), which is further confirmed by stereochemical analysis; (2) Cycle I is competitive with Cycle II, and the rate-determining steps of these two cycles are oxidation of Au(I) species by Selectfluor; (3) water has been found to participate in the catalytic reaction and decrease the activation energy barrier of the reductive elimination.