Reinvestigation of the linear free energy relationship on the solvent effects in the solvolysis of arylalkyl tosylates

重新研究甲苯磺酸芳烷基酯溶剂解中溶剂效应的线性自由能关系

• 批准号: 02640398
• 负责人: MIZUE Fujio
• 金额: $ 1.34万
• 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-02640398/
• 关键词: Solvolysis; Solvent Effects; Winstein-Grunwald Equation; Ionizing Power; Nucleophilicity; Solvation; 溶媒効果; ソルボリシス機構

The Winstein-Grunwald Equation, log (k/k_o) = mY + 1N, has been widely used as a mechanistic probe for analyzing the solvolytic processes. Despite the nucleophilically limiting nature of aryl-assisted and benzylic solvolyses, the solvent effect on these solvolyses failed to give a single linear correlation with the adamantyl Y_<OTs> parameter but showed characteristic dispersion for various binary aqueous solvent series. The pattern of dispersion can not be explained by simply Invoking the nucleophilic solvent assistance. Developing charge at the reaction center in the transition state of benzylic k_c carbocationic process is highly delocalized through effective PI-overlapping with aryl group, and this may cause a significant loss of the highly oriented specific solvation at the reaction center In comparison with that for aliphatic localized 2-adamantyl cation.Detailed examination of ionizing power scale most suitable to the aryl-assisted solvolysis as well as to the benzylic solvolyses, has been carried out in the comparison with the Y_<OTs> solvent scale based on the solvolysis of 2-adamantyl tosylate. The solvent polarity scale Y_<DELTA> based on p-methoxyneophyl solvolysis combined with the Y_<OTs> based on 2-adamantyl one has been found to show wide applicability to the solvolyses of benzylic arylalkyl tosylates involving varying degree of PI-delocalization interaction with the incipient carbocation charge ; log (k/k_o) = aY_<OTs> + bY_<DELTA>. Benzylic solvolyses can be treated to an extremely high precision R>0.995 and SD<0.15 with linear combination of Y_<OTs> and Y_<DELTA>. Application of revised equation, aY_<OTs> and bY_<DELTA> Including cN_<OTs> term has also been extended to the nucleophilic solvolyses of alkyl and arylalkyl tosylates, with limited success, indicating no precise additivity for the nucleophilic solvent involvement.

Winstein-Grunwald方程log (k/k_o) = mY + 1N已被广泛用作分析溶剂分解过程的机制探针。尽管芳基辅助溶剂解和苯基溶剂解具有亲核限制性质，但溶剂对这些溶剂解的影响与金刚烷基Y_<OTs>参数没有单一的线性关系，而是在各种二元水溶液系列中表现出特征的分散。分散的模式不能简单地用亲核溶剂辅助来解释。在苯基k_c碳正离子过程的过渡态中，通过与芳基的有效pi重叠，在反应中心产生电荷，这可能会导致反应中心高度定向的比溶剂化的显著损失，而非脂肪族定域的2-adamantyl阳离子。通过与Y_<OTs>溶剂尺度的比较，详细考察了最适合芳基辅助溶剂分解和苯基溶剂分解的电离功率尺度。基于对甲氧基新酚溶剂解的溶剂极性标度Y_<DELTA>与基于2-adamantyl的溶剂极性标度Y_<OTs>广泛适用于涉及不同程度的pi离域与初始碳正离子电荷相互作用的苯芳烷基甲酯溶剂解；log (k/k_o) = aY_<OTs> + bY_<DELTA>。在Y_<OTs>和Y_<DELTA>的线性组合下，苯解物的处理精度R>0.995， SD<0.15。修正方程aY_<OTs>和bY_<DELTA>（包括cN_<OTs>项）的应用也被推广到烷基和芳基烷基tosylates的亲核溶剂溶解，但取得了有限的成功，表明亲核溶剂参与没有精确的加性。

项目成果

M. Fujio: "Solvent Effect on the Solvolysis of 1-(p-Methoxyphenyl)-2, 2-dimethylpropen-1-yl Tosylate" Tetrahedron Lett. 33. 1309-1312 (1992)

M. Fujio：“溶剂对 1-(对甲氧基苯基)-2, 2-二甲基丙烯-1-基甲苯磺酸酯溶剂分解的影响”Tetrahedron Lett。

M.Fujio: "Solvent Effects on the Solvolysis of Neophyl Tosylates" Bull.Chem.Soc.Jpn.65. 46-54 (1992)

M.Fujio：“溶剂对 Neophyl 甲苯磺酸盐溶剂分解的影响”Bull.Chem.Soc.Jpn.65。

Y. Tsuji: "Solvent Effects on the Solvolysis of t-Butylbenzyl Tosylate" Tetrahedron Lett. 33. 349-352 (1992)

Y. Tsuji：“溶剂对甲苯磺酸叔丁基苄酯溶剂分解的影响”四面体快报。

M. Mishima: "Gas Phase Basicities of Acetophenones toward Trimethylsilyl Cation" Chem. Lett.493-496 (1992)

M. Mishima：“苯乙酮对三甲基甲硅烷基阳离子的气相碱度”化学。

M.Fujio: "Solvent Effect on the Solvolysis of 1ー(pーMethoxyphenyl)ー2,2ーdimethylpropenー1ーyl Tosylate" Tetrahedrom Lett.

M.Fujio：“溶剂对 1-(对甲氧基苯基)-2,2-二甲基丙烯-1-基甲苯磺酸酯溶剂分解的影响”四面体快报。