Theoretical Study On The Mechanism Of Transition Metal-catalyzed Functionalization Of Allylic Alcohols And Carbonyl Compounds

Theoretical and computational chemistry and physical chemistry,materials science,molecular chemistry,computational science and other related disciplines have a strong crossover and penetration,gradually become the forefront of today's chemistry,application is very wide.It studies the most core laws of chemistry and makes contributions to the further theoretical research of other branches of chemistry.For example,there will be some phenomena in the process of experiments that cannot be explained by existing chemical laws,which will limit the development of new materials and energy sources,as well as the application of existing metal-organic compounds.Quantum mechanics plays a particularly important role in the study of metal-organic catalytic reactions in this discipline.Transition metal organic chemistry has attracted the attention of contemporary researchers because of its high stability,selectivity and activity.In the development of modern science,metal-organic chemistry has been widely used in medicine,environment,new energy,materials and human life.By combining theoretical and computational chemistry with metal-organic chemistry,the key factors in the experimental process are explored,such as the choice of optimal reaction path,the causes of selectivity,the steps that determine reaction rate,etc.Theoretical and computational chemistry can calculate the optimal intermediate and transition state of the reaction in detail,and find out the most stable structure,so as to extract the corresponding energy,and further explore the nature behind the experimental phenomenon,which has important research significance and development prospect,and provides the basis and clues for the expansion of new reactions.In this paper,the reaction mechanism of Ni/Cu and Rh transition metal organic catalysis system has been discussed in detail by using density functional theory(DFT).Section 1:The mechanisms of the Ni/Cu-catalyzed silicification of allyl alcohols were investigated by employing the density functional theory(DFT)calculations.Five main steps are included in the reaction:initialization of reactants,oxidative addition,transmetalation,reductive elimination and regeneration of Cu catalyst.Among them,oxidative addition involving the initialized allyl alcohol,Ni catalyst and Cu catalyst is calculated to be the rate-and regioselectivity-determining step.The Cu catalyst employed in the experiment can improve both the stability and activity of the catalyst.In this reaction,different ligand would lead to different product.The origins of the ligand-controlled regioselectivity were clarified through our calculations.By using PEt₃ligand,the formed branched allylsilanes product was caused by the steric effects.While the 8-(diphenylphosphanyl)quinoline ligand would lead to the linear product due to the existed steric repulsion and coordination interaction.Section 2:The reaction mechanisms of Rh-catalyzed annulation of 2-arylindoles with?-diazo carbonyl compounds were investigated by employing the density functional theory(DFT)calculations.Five main steps are included in this reaction:N-H bond activation,C-H bond activation,N₂dissociation,migratory insertion of carbine,and protonation.The rate-determining step is calculated to be the combined process of C-H bond activation and N₂dissociation.