Theoretical Study On Unactivated Olefins Catalyzed By Transition Metal (Ir, Ni) Complexes

Transition metal complexes catalyze the reaction of unactivated olefins with specific substrates,which is a hot research direction of organic synthesis in recent years.In particular,transition metal catalysts such as iridium,nickel,palladium,etc.have good reactivity in some chemical reactions,and are the key factors affecting the reaction and yield.Therefore,the specific and detailed theoretical research contents of the reaction mechanism of such reactions have very important guidance and reference value for the same type of reactions and the development of new catalysts.In this paper,the reaction mechanism of transition metal iridium and nickel catalyzed olefins was studied by density functional theory(DFT).The research content mainly includes the following two parts:1.Ir catalyzes the alkylation ofα-C(sp~3)-H bond-saturated nitrogen heterocycles.The research content of this reaction includes the exploration of reaction pathways and the analysis of regioselectivity.By analyzing the Ir-H migration insertion/C-C reduction elimination reaction pathway and the Ir-C migration insertion/C-H reduction elimination reaction pathway,the reaction pathway was finally determined as Ir-H migration insertion/C-C reduction elimination and the reason was reasonably explained.Therefore,the sequence of the whole alkylation reaction is determined as the coordination of the reaction substrate pyrrolidine and the catalyst,the oxidative addition of the C-H bond,the alkene coordination of the acrylate,the migration and insertion of the Ir-H bond and the C-C reduction and elimination process.The calculation results show that the apparent activation energy of the alkylation reaction of pyrrolidine and acrylate to form branched products is 29.0 kcal/mol,and the apparent activation energy of linear products is 35.8 kcal/mol,and the calculation results are consistent with the experimental results.It shows that the main product of the reaction is a branched chain product.2.Ni catalyzes the acylation of unactivated alkenes.By analyzing the processes of C-F bond activation,carbocyclization,and conversion with phenylboronic acid,the reaction mechanism of the reaction was clarified and explained in detail.Therefore,the sequence of the entire acylation reaction was determined as follows:coordination of reaction substrate carbamoyl fluoride with catalyst,oxidative addition of C-F bond,carbocyclization of transition metal Ni complex,conversion with phenylboronic acid,and C-C reduction and elimination process.The calculation results show that the apparent activation energy of the product produced by this reaction is 46 kcal/mol.On Iridium catalyzed saturated nitrogen heterocyclesα-C(sp~3)-H bonds Key of the alkylation and the nickel catalyzed acylation of unactivated alkenes,reactive intermediates and transition states that are difficult to obtain in chemical experiments,the detailed mechanism of the reaction.And by detailed reaction mechanism and analysis of issues such as regioselectivity,a relevant theoretical basis is provided for such studies.