ESR spectroscopic investigation of steric and polar factors in the addition of radicals to unsaturated compounds
摘要:
The rate constants of the addition of CCl3CH2CClCH3(R6) radicals to alpha-methyl-styrene, styrene, methyl methacrylate, methyl acrylate, and acrylonitrile and of CCl3CH2C(CH3)2(R7) radicals to styrene, methyl acrylate, and acrylonitrile were determined by ESR spectroscopy. It was shown that the radicals R6 and R7 possess approximately equal reactivity in addition to unsaturated compounds, despite the difference in the donor-acceptor properties of the substituents at the vinyl group. In a comparison of the reactivity of radicals R6 and R7 with the reactivity of radicals CCl3CH2CH2(R1), CCl3CH2CHCH3(R3), CCl3CH2-CHCl(R4), and ClCH2CH2CCl2(R5) [1] in addition reactions, it was shown that polar and steric effects of the substituents situated in the alpha-position to the radical site of the above-mentioned radicals, as well as the donor-acceptor properties of the substituents at the vinyl group in the unsaturated compounds, lead to appreciable changes in reactivity.
Etude de la reaction d'oxydation d'alcools par voie organostannique
作者:Jean-Claude Pommier、Daniel Chevolleau
DOI:10.1016/s0022-328x(00)83685-2
日期:1974.7
alkoxides react with polyhalomethanes under freeradical conditions leading to the corresponding carbonyl compounds. Two secondary reactions generally occur, giving an alcohol and polyhalo derivatives of pentane. Investigation of the mechanism showed that the oxidation begins by attack on a hydrogen borne by the alkoxylated carbon, followed by rapid expulsion of the R3Sn. radical. The formation of alcohol
有机锡醇盐在自由基条件下与多卤代甲烷反应,生成相应的羰基化合物。通常发生两个次级反应,得到戊烷的醇和多卤代衍生物。对该机理的研究表明,氧化开始于攻击烷氧基化碳所携带的氢,然后迅速排出R 3 Sn 。激进的。戊烷的醇和多卤代衍生物的形成通过CCl 3的攻击而发生。锡原子上的自由基,随后消除RO 。自由基或通过氢在三丁基锡基团的β碳原子上的夺取而生成烯烃,该烯烃添加了多卤代甲烷分子。