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The Study of Generating Stabilized Phenyl Cations by Using New Super-Leaving Groups

利用新型超离去基团生成稳定苯基阳离子的研究

基本信息

批准号：
07640726
负责人：
SONODA Takaaki
金额：
$ 1.47万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07640726/
关键词：
Trifyl-substituted Heteroatom Functional Group Phenyl Cations Structure and reactivity Molecular Orbital Method Calculation Analysis of Substituent effects Solvolysis Reactions Weakly-Coordinating Polyfluorinated Organic Anions 反応性炭素陽イオン中間体

项目摘要

Various alkali metal, alkali-earth metal, and transition metal ions ion-paired with weakly-coordinating polyfluorinated organic anions such as OSO_2CF_3, N (SO_2CF_3) _2, and C (SO_2CF_3) _3 were examined as strong Lewis acids in catalytic Diels-Alder reactions and halochromism of azo-dye compounds in nonpolar organic solvents to investigate the coordinating and leaving abilities of the organic anions.The photosolvolysis of aryl triflates in fluorinated alcohols was proved to proceed via aryl cation intermediates, while the photo-and thermal-solvolysis of aryl ester ArOS (O) (CF_3)=C (SO_2CF_3) _2 gave the products derived from the ArO-S (O) bond cleavage.The experimental relative rate-constant for the dediazoniation reactions of para- and meta-substituted benzenediazonium ions in solution was good correlated with the computational relative stabilizing energy of the corresponding phenyl cations with para- and meta-substituents, respectively. The phenyl cations with electron-donating substituents on meta-position are highly stabilized by novel direct-conjugation with the meta-substituents.Experimental evidences of this novel effect of meta-substituent for stabilizing phenyl cation intermediates in the thermal-solvolysis of the aryl triflate with piperidinyl groups at 3,5-positions were demonstrated : exclusive formation of solvent-substituted products and solvent polar effect in the solvolysis in TFE,HEIP,and aqueous HFIP indicated the S_N1 mechanism of the solvolysis to proceed via ary1 cations highly stabilized by the meta-substituents.

各种碱金属、碱土金属和过渡金属离子与弱配位的多氟有机阴离子如OSO_2CF_3、N（SO_2CF_3）_2，和C研究了（SO_2CF_3）_3作为强刘易斯酸催化Diels-Alder反应和偶氮-研究了三氟甲磺酸芳基酯在非极性有机溶剂中的光溶剂分解反应，考察了有机阴离子的配位和离去能力，通过芳基阳离子中间体进行，而芳酯ArOS（O）（CF_3）=C的光、热溶剂分解（SO_2CF_3）_2的脱重氮反应的实验相对速率常数分别为：ArO-S（O）键断裂反应的相对速率常数为：ArO-S（O）键断裂反应的相对速率常数为取代的重氮苯离子在溶液中与相应的苯基阳离子的计算相对稳定化能有很好的相关性，帕拉和间位取代基。间位上具有给电子取代基的苯基阳离子通过与间位取代基的新型直接共轭而高度稳定。在3，5-位上具有哌啶基的三氟甲磺酸芳基酯的热溶剂分解中，间位取代基对稳定苯基阳离子中间体的这种新型作用的实验证据被证明：在TFE、HEIP和HFIP水溶液中，溶剂分解过程中只生成溶剂取代产物和溶剂极性效应，表明溶剂分解的S_N1机理是通过间位取代基高度稳定的芳基阳离子进行的。