Mechanistic Studies on The Thermal [m+n] Cycloadditions of 8-Aryl-8-azaheptafulvenes and 8,8-Dicyanoheptafulvene with 2-(2,4-cyclopentadien-1-ylidene)-1,3-dithiolane
| Autor: | 陳祥光 |
|---|---|
| Rok vydání: | 2003 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 91 In order to determine the product selectivity, this investigation involves the synthesis and [m + n] cycloadditions of 8,8-dicyanoheptafulvene 8a and 8-aryl-8-azaheptafulvenes 13a-c with electron-rich substituted fulvene (electron-rich 2-(2,4-cyclopentadien-1-ylidene)-1,3- dithiolane 26), designed to establish the scope and limitations, and to determine the factors which control the reactivity, periselectivity, and regioselectivity of these cycloadditions. The cycloaddition reactions of electron-deficient 8,8-dicyanoheptafulvene 8a with electron-rich 2-(2,4-cyclopentadien-1-ylidene)-1,3-dithiolane 26 at lower temperature (80℃) gave [8+2] adduct 27 and [4+2] adduct 28 and 29. When the reaction was carried out at higher temperature (140℃), only [4+2] adducts 28, 29 and 30 were obtained. However, the cycloaddition reaction of electron-rich 8-aryl-8-azaheptafulvenes 13a-c with electron-rich 2-(2,4-cyclopentadien-1-ylidene)-1,3-dithiolane 26 did not give any cycloaddition product. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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