Computational Exploration Of The Mechanism Of Organic Reactions:Rh(?)-catalyzed Decarbonylation Reaction And Acid-promoted Inverse-electron Demand Diels-alder Reaction

Theoretical and computational chemistry has been an important part of chemistry. It has draw more attention for its outstanding contributions on the understanding the mechanisms of chemical reactions, especially catalysis. To research the mechanism of a chemical reaction with computational methods, several aspects are usually included in a study:1. the process of the reaction; 2. the intermediates and transition states in the process; 3. the real catalyst and the rules it played; 4. the dynamic and thermodynamic data of each step in the whole process; 5. the selectivities of the reaction and their orlgins.With the researches showing above, detailed informations of the reaction could be observed. Chemists could optimize the reactions, create new reactions and desire new catalysts with the benefit of the computational chemical data.In this paper, we use computational methods to deeply study the mechanisms of two reactions and further study the selectivities and reactivities of the reactions. The first project is about the reaction of rhodium catalyzed decarbonylation of ynones. Two systems of different ynones and catalysts has been studied in this paper: diynones with rhodium-dppf catalyst system and monoynones with rhodium-xantphos catalyst system. The mechanisms of each reaction system are studied using computational methods, finding out the rate-limiting step. Selectivities, reactivities of catalysts and substrates are studied as well and new models are proposed to solve one of the selectivities.The second project is about a cascade reaction of inverse-electron demand Diels-Alder reaction and retro Diels-Alder reaction between ketones/aldehydes and 1,3,5-triazines. It was proposed that the ketones/aldehydes would take part in the reaction by isomerizing to enol form. Alkenyl ethers are regarded as analogues of enol but more reactive than enols. Surprisingly, alkenyl ethers cannot react with 1,3,5-triazines under the standard conditions. In this paper, a computational study has been proceeded to explore the mechanism this reaction and try to give a rational explanation of the different reactivities between alkenyl ether and ketone/aldehyde.