A Theoretical Study On Isomerization Mechanism Between Ketone And Enol Compounds Assisted By Water Molecules

Based on density functional theory(DFT) and B3LYP method and MP2 method, we made a theoretical study of the reaction system involving ketone compound. We studied the mechanism of each reaction. We determined the structure of the reactants, intermediates, products and transition states, and discussed the change of the structures in all the reactions.A theoretical study on the isomerization mechanism between ketone and enol compounds MeC(=O)(CH₂R) and MeC(OH)(=CHR) assisted by water molecules were carried out with the MP2 methods. The optimal structures of ketone, enol, and transition states were located and the reaction barriers were predicted. The calculation results show that among all 14 reactions studied in this paper, the reaction barrier is lowered for the electron withdrawing group and for the group with unoccupied orbital whereas it is raised for the electron donation group without unoccupied orbital. The calculation results suggest that the intramolecular process is kinetically unfavorable because the high barrier exists whatever the substituent is. The one water-assisted process is less favorable either. The process assisted by two water molecules is the most favorable because the low barrier exists whatever the substituent is.Based on density functional theory(DFT) and B3LYP method, we made a theoretical study of the reaction system involving acetone and benzene carbonal catalyzed by L-proline.The single point energy and frequency of each structure was calculated. The calculation results show that R configuration was primary when reaction was between acetone and benzene carbonal catalyzed by L-proline.