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A New Type of Nonbenzenoid Aromatic Carbocation : 1, 6-Methano[10]AnnulenylCation.

一种新型非苯环芳香族碳正离子：1, 6-甲醇[10]环烯基阳离子。

基本信息

批准号：
02804041
负责人：
SONODA Takaaki
金额：
$ 1.15万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02804041/
关键词：
Reactive intermediate Nonbenzenoid aromatic compound Carbocation Quantum chemical calulations

项目摘要

The structure-reactivity relatioship of a new type of nonbenzenoid aromatic carbocation with a positive charge on an unsaturated carbon atom, 1, 6-methano[10]annulen-2-yl cation, was investigated by theoretical and experimental methods.a. A comparison of experimental results in solvolysis with theoretical calculations by semiempirical MO methods with respect to the structure-stability relationship of carbocations with a positive charge on an unsaturated canbon atom indicated that the carbocation 30 kcal/mol more stable than phenyl cation can be generated in the S_N1 solvolysis of the corresponding triflate precursors.b. Incontrast to planar 1-naphthyl cation, 1, 6-methano[10]annulen-2-yl cation is highly stabilized by the delocalization of the positive charge on C-2 atom into 10 pi electron system because of its nonplanar structure and the contribution of a limiting allene structure.c. 1, 6-Methano[10]annulen-2-ylcation was generated in gas phase from the corresponding annulenyl bromide derivative.d. The solvolysis of the annulenyl triflate in trifluoroethanol (TFE) gave complex mixtures containing some products by triflate substitution with TFE solvent.e. An experiment of quantitative dideuterio substitution of the 2, 7-dibromoannulene derivative indicated a possibility of the generation of the annulenyl cation in the beta-decay decomposition of the corresponding 2, 7-ditritioannulene derivative in gas phase and solution phase.

采用理论和实验方法研究了一种带正电荷的新型非苯芳香族碳正离子1,6 -甲烷环壬-2-基阳离子在不饱和碳原子上的结构-反应关系。用半经验MO方法对不饱和碳原子上带正电荷的碳正离子的结构-稳定性关系进行了溶剂解实验结果与理论计算结果的比较，结果表明，相应的三氟酸盐前驱体在S_N1溶剂解中可以生成比苯基阳离子稳定30 kcal/mol的碳正离子。与平面的1-萘基阳离子相比，1,6 -甲烷环环-2-基阳离子由于其非平面结构和限制烯结构的贡献，使C-2原子上的正电荷离域到10 π电子系统中，具有很高的稳定性。相应的环溴衍生物在气相中生成1,6 -甲烷环烯-2基化反应。在三氟乙醇（TFE）中，三氟磺酸环烯酯通过三氟磺酸取代得到了含有某些产物的复杂混合物。2,7 -二溴环烯衍生物的定量双氘取代实验表明，相应的2,7 -二溴环烯衍生物在气相和溶液相的β衰变分解中有可能生成环烯基阳离子。