| Summary: In this thesis, Diels-Alder reactions of some caged molecules were quantum chemically studied and the obtained results were compared with the experimental results which contain in literature. Optimization of caged molecules in each reaction system was calculated by density functional theory (DFT) method at B3LYP level and the geometrical and electron structures of the molecules were investigated. Mutual interactions of the reactants in the Diels-Alder reactions according to the frontier orbital theory were investigated by the B3LYP/6-31+G(d,p) method. The molecular electrostatic potential (MEP) maps of each caged diene molecule were derived from the optimized geometries of the B3LYP/6-31+G(d,p) method to determine the regio and stereoselectivity of the caged diene molecules in the related reactions. The geometric optimizations of the transition states and products corresponding to the critical points on the potential energy surface of the reactions were performed by the B3LYP/6-31+G(d,p) method and their structure and stability were compared to each other. In order to insight the structures of the transition states, the bond formation lengths and bond order of transition states of each Diels-Alder reaction were calculated. In addition, the kinetic parameters of transition states and the thermodynamic parameters of the products in each reaction were calculated by the B3LYP/6-31+G(d,p) method to determine under which control (thermodynamic/kinetic control) the related reaction take place. The results obtained by thetheoretical calculations were compared with the experimental results containing in literature and it was determined that both results are compatible with each other in each reaction system. |
