Theoretical Study of the Mechanism of Palladium-Catalyzed Arylation of Alkenyl Carboxylates

Palladium-catalyzed cross-coupling of an organometallic nucleophile is one of the most important C–C bond forming methods in almost all areas of synthetic chemistry. We investigate the potential energy surfaces of the Pd-catalyzed arylation of alkenyl carboxylates using density functional theory and try to elucidate their mechanisms. The reactions involving Pd(0)/(II) and only Pd(0) are studied in detail. The results show that these two kinds of reactions have feasible reaction pathways under mild condition. The most feasible reaction channels are Pathways A and C through a three-membered ring transition state with the highest energy barriers of 21.4 kcal/mol relative to the reactant, indicating that they can occur even at room temperature. When C 6 H 5 free radical is produced, the energy barrier of Pathway B is the highest with a value of 33.5 kcal/mol relative to the reactant, which can occur under the experimental condition with a temperature of 60°C.