Theoretical Study Of Rhodium And Palladium Catalyzed The CH Functionalization Of Benzamides

The study of transition metal-catalyzed reaction mechanisms is the most active and important subject in the field of computational organic chemistry.Especially in recent years,with the increase of calculation speed and the continuous progress of modern theoretical methods,the use of quantum chemistry methods to study the reaction mechanism and reaction kinetic parameters has aroused great interest from theoretical chemists and experimental chemists.However,in recent years,with the increasing pollution of the environment and the depletion of earth resources consumed by people,the development and update of new catalyst-catalyzed reactions and the realization of the purpose of green chemistry to complete the green conversion of substances have become current chemistry Focus and cutting-edge areas of worker research.To improve and develop new types of catalytic reactions,we must further deepen our understanding and understanding of the relevant catalytic reaction mechanisms.Therefore,we started the research on the reaction mechanism catalyzed by transition metals.In this paper,we have studied the reaction mechanism of two catalytic systems in detail using density functional theory.Using DFT calculations,we explore and explain the detailed reaction mechanism of the two systems.In addition,we hope that the calculated conclusions can provide corresponding theoretical basis and guidance for related experimental work in the future.The specific work are as follows:Part 1:The reaction mechanisms of Rh-catalyzed C-H allylation of benzamide with1,3-diene were investigated by employing DFT calculations.Five main steps are included in this reaction:N-H bond activation,C-H bond activation,olefin insertion,1,4-Rh migration,and?-hydride elimination.The rate-determining step is?-hydride elimination according to our calculations.Lam et al have proposed three possible mechanisms for the 1,4-Rh migration,but the barriers are calculated to be high.In contrast,the H-migration process from methyl group to N center and to C4 center successively is the most feasible one,consistent with the deuterium transfer experiment.Part 2:The mechanistic study of palladium-catalyzed intramolecular chemoselective C(sp~2)-H and C(sp~3)-H activation of N-Alkyl-N-arylanthranilic acids was carried out by using DFT.Our calculated results indicate that when the oxidant is silver oxide,the oxidant participates in the cycle,Pd/Ag bimetallic promoting C(sp~3)-H activation/reduction elimination to provide 1,2-dihydro-(4H)-3,1-ben-oxazin-4-one.The rate-determining step is reduction elimination according to our calculations.When the oxidant is copper acetate,the catalyst is palladium alone,it helps decarbonylation reaction/C(sp~2)-H activation to provide carbazoles.The rate-determining step is C(sp~2)-H activation.These are consistent with experimental results.