Quantitative aspects of radical addition. Part IV. Rate-constant ratios for addition of trichloromethyl and thiyl radicals to olefins
作者:J. I. G. Cadogan、I. H. Sadler
DOI:10.1039/j29660001191
日期:——
and trichloromethyl radicals from bromotrichloromethane. In a number of experiments both the unchanged olefins and the 1 : 1 adducts were estimated, thus accounting, for the first time, for all the olefin in the system. The results, while confirming the electrophilic character of the radicals studied, indicate that no single factor is entirely responsible for the variations in olefin reactivity. The absence
考察了影响自由基加成至烯烃双键的速率的因素,并特别提到了极性,共振和空间现象的相对重要性。一种有效的竞争方法已被用来衡量取代反式的相对反应性-对苯二甲酸酯,取代的苯乙烯和各种脂族烯烃,它们来自硫代乙醇酸及其甲基酯的噻吩基,以及来自溴代三氯甲烷的三氯甲基基团。在许多实验中,估计了未改变的烯烃和1:1加合物,因此首次考虑了系统中所有烯烃。结果证实了所研究自由基的亲电特性,但表明没有单一因素完全负责烯烃反应性的变化。已经确定,在将硫代基团添加到取代的α-甲基苯乙烯中时,对过渡态没有明显的极性贡献。