Correlation of the rates of solvolysis of cyclopropylcarbinyl and cyclobutyl bromides using the extended Grunwald-Winstein equation
Correlation of the rates of solvolysis of cyclopropylcarbinyl and cyclobutyl bromides using the extended Grunwald-Winstein equation
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DOI：
10.1021/jo991904
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发表时间：
2000-04-21
影响因子：
3.6
通讯作者：
Abduljaber, MH
中科院分区：
文献类型：
--
作者：
Kevill, DN;Abduljaber, MH
环丙基溴化原酯（1）和环丁基溴化原酯（2）在含羟基溶剂中的反应既有溶剂分解又有重排反应。根据溶剂的不同，1的反应比2的反应快10-120倍，两者都比以前研究的烯丙基溴化原快（3）。具体的速率报告的反应2进行溶剂分解产物和3。1的反应进行溶剂分解产物和2和3;由于2缓慢地进行进一步的溶剂分解，通过修改的古根海姆处理获得特定的速率。使用扩展的Grunwald-Winstein分析了两组特定速率。方程给出了对溶剂亲核性变化的灵敏度，对于1为0.42，对于2为0.53，以及对溶剂电离能力变化的相应灵敏度为0.75和0.94。提出了一种机制，涉及一个速率决定电离与一个明显的亲核溶剂化的初期碳正离子。
The reactions of cyclopropylcarbinyl bromide (1) and cyclobutyl bromide (2) in hydroxylic solvents proceed with both solvolysis and rearrangement. Depending on the solvent, the reactions of 1 are 10-120 times faster than those of 2, and both are faster than the previously studied allylcarbinyl bromide (3). Specific rates are reported for the reactions of 2 proceeding to solvolysis products and 3. Reactions of 1 proceed to solvolysis products and both 2 and 3; since 2 slowly undergoes further solvolysis, specific rates are obtained by a modified Guggenheim treatment. The two sets of specific rates are analyzed using the extended Grunwald-Winstein. equation to give sensitivities toward changes in solvent nucleophilicity of 0.42 for 1 and 0.53 for 2 and corresponding sensitivities toward changes in solvent ionizing power of 0.75 and 0.94. A mechanism is proposed involving a rate-determining ionization with an appreciable nucleophilic solvation of the incipient carbocation.