| N-4-戊烯基硝酮分子内环加成反应区域选择性的理论研究 |
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| 引用本文： | 马思渝,傅孝愿.N-4-戊烯基硝酮分子内环加成反应区域选择性的理论研究[J].高等学校化学学报,1992,13(6):837-839. |
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| 作者姓名： | 马思渝 傅孝愿 |
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| 作者单位： | 北京师范大学化学系, 北京, 100875 |
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| 基金项目： | 国家教育委员会博士点基金 |
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| 摘 要： | N-烯基硝酮分子内环加成反应具有区域选择性,如图1.当n=2,R~1=R~2=R~3=H时,即N-4-戊烯基硝酮分子内环加成反应.实验表明,P_a的产率为23％,P_b为47％.我们曾用MINDO/3方法对此反应进行IRC计算,确证P_a、P_b是经由反应物两种不同构象(R_a、R_b)分别得到的产物,并讨论了二反应活化势垒的差别对区域选择性的影响.Tufariello等人认为,P_b的较高产率主要由于2个产物的过渡态的熵差别.为此,本文从理论上考察活化熵和活化焓对区域选择性的影响.
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| 关 键 词： | 区域选择性 N-4-戊烯基硝酮 分子内环加成反应 |
| 收稿时间： | 1991-04-21 |
Theoretical Study on the Regioselectivity of Intramolecular N-4-pentenyl Nitrone Cycloaddition |
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| MA Si-yu,FU Xiao-yuan.Theoretical Study on the Regioselectivity of Intramolecular N-4-pentenyl Nitrone Cycloaddition[J].Chemical Research In Chinese Universities,1992,13(6):837-839. |
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| Authors: | MA Si-yu FU Xiao-yuan |
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| Institution: | Department of Chemistry, Beijing Normal University, Beijing, 100375 |
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| Abstract: | The reaction mechanism of the intramolecular cycloaddition of N-4-pentenyl nitrone was investigated theoretically by using AM1 MO method and transition state theory. There are two parallel reactions leading to two different regioisomers. The geometries of the reactants, TS and products were optimized. The ratio of the rate constant of the two reactions is 1. 2 (at 383. 75 K) and is in good consistence with experiments. |
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| Keywords: | Regioselectivity N-4-pentenyl nitrone Intramolecular cycloaddition |
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