Studies On The Mechanism Of Formation Of Ketones By Palladium-catalysed Desulfitative Reaction

Since C-C bond is the main skeleton of organic compounds, it is very important to develop a new method to construct the C-C bond. The coupling reaction catalyzed or participated by transition metal palladium is widely applied to the construction of C-C bond, so it is of great significance to study the palladium-catalyzed coupling reaction. In this work, we have studied the mechanisms of the two projects, one at the Becke3 LYP level of DFT and the other at the M06 level of DFT. Frequency calculations at the same level of theory were also conducted to verify all the stationary points as minima or transition states and to provide free energies at 298.15 K. The intrinsic reaction coordinate analysis was carried out to confirm that all stationary points are smoothly connected to each other. The lanl2 dz basis set was used for Pd and S atom and the 6-31g*basis set was used for other atoms. The purpose is to provide reasonable reaction mechanisms and explain the experimental phenomena and results, meanwhile the research results will provide theoretical guides for the related experimental studies.(1) The Pd(OAc)2-catalyzed reaction of benzenesulfinic acid with benzonitrile forming diphenylketone has been studied theoretically with the help of density functional theory.Researches show that the acetate in the catalyst was found to directly participate in the reaction, and the additive H2SO4 played an important role in the catalytic reaction.(2) The Pd(CO2CF3)2-catalyzed reaction of benzenesulfinic acid with benzonitrile forming diphenylketone has been studied theoretically with the help of density functional theory.Results show that the trifluoroacetate in the catalyst can directly participate in the reaction.Moreover, the free energy barrier of each step using catalyst Pd(CO2CF3)2 was lower than that using catalyst Pd(OAc)2, indicating that catalyst Pd(CO2CF3)2 is better than catalyst Pd(OAc)2 in the reaction.