The Study on the Mechanism of Conjugative Stabilization of Phenyl Cations

苯基阳离子是一种高活性的重要合成中间体，1）对取代苯基阳离子的优化结构进行了半经验和从头算计算，结果表明，Meta位带有给电子基团的高度稳定的苯基阳离子具有“非平面”结构2）2-丙基苯基氯的光溶剂分解反应通过2-丙基苯基阳离子中间体得到产物，该中间体类似于2-丙基重氮苯离子的热分解反应; 3）溶剂、间位取代基的给电子能力、和离去基团的电子亲合势对通过芳基自由基和芳基阳离子中间体的两种产物的比例的影响，4）邻羟基苯氯的光溶剂解反应中，中间体氧化苯基阳离子的缩环反应与亲核溶剂对羟基苯阳离子的进攻反应竞争进行。实验结果进行了研究，通过计算计算。

This is a fundamental research to investigate the structure-reactivity relationship of phenyl cations, which are highly reactive and important intermediates for synthesis, with respect to the mechanism of the conjugative stabilization of phenyl cations.1)Semi-empirical and ab initio calculations on the optimized structures of substituted phenyl cations revealed that highly stabilized phenyl cations with electron-donating groups at meta position have "non-planar" structures, whose stability and nonplanality are closely related.2)Photosolvolysis of 2-propylphenyl chloride gave rise to the products via 2-propylphenyl cation intermediate which were similarly obtained in the thermal decomposition of 2-propylbenzenediazonium ions.3)The effects of solvents, electron-donating ability of meta-substituents, and electron-affinity of leaving grous on the ratio of two products via aryl radical and aryl cation intermediates were investigated in the photo-solvolysis of aryl triflates and chlorides, where hydrogen abstraction of aryl radicals from solvent and nucleophilic attach of solvent on aryl cations occured competitively.4)In the photo-solvolysis of ortho-hydroxyphenyl chloride ring contraction of the intermediate oxido-phenyl cations occured competitively with the nucleophilic solvent attack on the hydroxyphenyl cations. The experimental results were investigated by computational calculations.