Density Functional Theory study of [8+2] and [4+2] Cycloaddition Reactions of 2-Oxo-2H-cyclohepta[b]furan derivatives with Dienes
| Autor: | Chun-Chia Lai, 賴俊嘉 |
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| Rok vydání: | 2002 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 90 Cycloaddition reactions of 2-Oxo-2H-cyclohepta[b]furan derivates participating as 8π and 4π components respectively toward dienes are described. We use density functional theory (DFT) calculations in the study of transition states and products of title reactions. Possible [4+2] and [8+2] reaction paths were investigated. Our results show that Part 1: [8+2] endo path, is the most likely both thermodynamically and kinetically. The distinct selectivity of the [8+2] endo path over the [4+2] endo one was explained in terms of the secondary orbital interaction (SOI). Part 2: we simulate the substituent effect and compare the result with experiment, the result shows that the more exothermic the reaction, the higer yield the product. Our theoretical prediction is consistent with the experimental observation. Part 3: we apply hetero-atom subsititutions, the result shows that new bicyclo compounds have more aromaticity, leading to increase in the relative energies of intermediates and transition structures. We thus conclude that the cycloaddition reactions with hetero-atom subsititutions are less likely to occur. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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