Catalytic C-H activation/C-C coupling reaction: DFT studies on the mechanism, solvent effect, and role of additive

摘要

A series of density functional theory (DFT) experiments, employing the B3LYP+IDSCRF/BS1 and B3LYP+IDSCRF/DZVP methods, have been carried out for the Pd(OAc)_2-catalyzed enamide-siloxane C-H activation/C-C coupling reactions. The results reveal that there are four processes, namely C-H activation, transmetalation (TM), reductive elimination (RE), and separation of product (SP) and recycling of catalyst (RC), each of which is consist of different steps. In order to fully understand the origin of regiospecific C-H activation/C-C coupling on the alicyclic ring experimentally observed, the conformational preference, kinetic aspects, and relative stabilities of the competitive products have been explored. In addition, the roles of additive silver salt AgF and solvent dioxane have also been addressed, providing valuable details upon which to rationally optimize experimental conditions.