A polar substituent effect on the ring-cleavage rearrangement of 1-arylcyclobutylmethyl Grignard reagents
作者:E.Alexander Hill、Baoju Li
DOI:10.1016/0022-328x(93)80060-o
日期:1993.4
first-order rate constants are correlated by the Hammett equation, with ϱ = −0.47. The results are consistent with a concerted mechanism with a cyclic transition state having significant polar character, although polar effects on the stabilities of reactant and product may also contribute. The phenyl group itself slows the reaction by a factor of 0.031, which is interpreted principally in terms of steric
已经确定了1-苯基环丁基甲基镁氯化物及其对甲基和对氯类似物的环断裂重排的动力学。一阶速率常数由Hammett方程关联,ϱ = -0.47。该结果与具有显着极性特征的具有环状过渡态的协调机制一致,尽管极性对反应物和产物的稳定性也有贡献。苯基本身使反应减慢了0.031倍,这主要是根据过渡态的空间不稳定来解释的。