Study on Ranking and Characteristic of Vinyl Cations as Carbocation

乙烯基阳离子碳正离子的排序及特性研究

• 批准号: 05453033
• 负责人: KOBAYASHI Shinjiro
• 金额: $ 4.29万
• 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 (B)
• 财政年份: 1993
• 资助国家: 日本
• 起止时间: 1993 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05453033/
• 关键词: vinyl cation; carbocation; resonance demand; substituent effect of beta-alkyl substituent; steric effect; solvent effect; solvolysis; photolysis; βアルキル基置換基効果; betaアルキル基置換基効果

The purpose of this study is how a divalent vinyl cation is connected with trivalent carbocations and how characteristic a vinyl cation is.1) Protonation to phenylacetylene derivatives in gas phase generates vinyl cations. The thermodynamics of various vinyl cations were evaluated with equation of linear relationship of aromatic substitution reaction. The r-values of b-substituted vinyl cations gave linear relationship with stability of the corresponding vinyl cations and also related with trivalent benzylic cations.2) Solvent effect of solvolysis of vinyl derivatives were measured in aqueous ethanol. The problem of solubility was overcome with preparation of vinyl derivatives which have a hydrophilic ammmono group. Further investigation has to be done in extension.3) A vinyl cation can be generated by laser flash photolysis of aryl-substituted vinyl halides. The behavior of a vinyl cation can be followed by measuring its decay rates under various solvolytic conditions. The nucleophilicity of solvent mixture is evaluated. There is large difference between beta-substituents of alpha-p-methoxyphenylvinyl cations due to steric repulsion between the beta-substituent and nucleophiles.

本研究的目的是了解二价乙烯基阳离子如何与三价碳阳离子连接以及乙烯基阳离子的特性如何。1）气相中苯乙炔衍生物的质子化产生乙烯基阳离子。用芳香族取代反应的线性关系方程评价了各种乙烯基阳离子的热力学。 b-取代乙烯基阳离子的r值与相应乙烯基阳离子的稳定性呈线性关系，也与三价苄基阳离子相关。2)在含水乙醇中测量乙烯基衍生物溶剂解的溶剂效应。通过制备具有亲水性氨基的乙烯基衍生物克服了溶解度问题。 3)芳基取代乙烯基卤化物经激光闪光光解可产生乙烯基阳离子。乙烯基阳离子的行为可以通过测量其在各种溶剂分解条件下的衰减速率来跟踪。评估溶剂混合物的亲核性。由于β-取代基和亲核试剂之间的空间排斥，α-对甲氧基苯基乙烯基阳离子的β-取代基之间存在很大差异。

项目成果

M.Fujio: "The Importance of Resonance Stabilization in the Benzylic Solvolysis.Substituent Effects on the Solvolysis of alpha,alpha-Diisopropylbenzyl Chlorides" Tetrahedron Lett.34. 8309-8312 (1993)

M.Fujio：“苄基溶剂分解中共振稳定性的重要性。取代基对 α,α-二异丙基苄基氯溶剂分解的影响”四面体 Lett.34。

S,Kobayashi: "Substitueut Effect on Gas Phase Basicity of 1-Phenylpropgne,Thermodynamic,Stability and Resonance Demand of 1-Phenylpropenyl Cations" Tetrahedron Lett,. 34. 5903-5906 (1993)

S，Kobayashi：“1-苯基丙烷气相碱度的取代效应，1-苯基丙烯基阳离子的热力学、稳定性和共振需求”四面体莱特，。