Effect of the leaving group solvation on solvolytic behavior of benzhydryl derivatives
作者:Bernard Denegri、Olga Kronja
DOI:10.1002/poc.1508
日期:2009.5
An effect of the leaving group (LG) solvation on reactivity of benzhydryl derivatives in SN1 reactions has been investigated by using X,Y‐substituted benzhydryl phenyl carbonates, methyl carbonates, 3,5‐dinitrobenzoates (DNB), and the corresponding benzhydryl chlorides as reference compounds. Reaction constants (sf) derived from LFER equation log k (25 °C) = sf(Nf + Ef) indicate that sf parameters
通过使用X,Y-取代的苯甲基碳酸苯酯,碳酸甲酯,3,5-二硝基苯甲酸酯(DNB)和相应的苯甲基,研究了离去基团(LG)溶剂化对S N 1反应中苯甲基衍生物的反应性的影响。氯化物作为参考化合物。反应常数(小号˚F从LFER方程日志导出)ķ(25℃)= 小号˚F(Ñ ˚F + È ˚F)表明小号˚F碳酸盐和DNB的参数随着给定溶剂/水混合物中水的比例增加而降低,而氯化物的参数保持不变。该现象归因于TS中不太重要的溶剂化和较少的电荷分离。使用各种溶剂电离功率标度,通过Grunwald-Winstein相关性分析了溶剂对反应速率的影响。的米为碳酸盐和的DNB获得的值比相当小的米为氯化物的值。而且,与电熔剂较弱的那些相比,电熔剂较强的底物的溶剂分解速率常数受溶剂的影响较小(m较低)。m的值在给定的二元溶剂系统中,给定底物获得的参数与所生成的苯甲鎓离子的电逸度密切相关。m = 0时的横坐标表示底