The solvent effect on the reaction constants of tert-butyl radical addition to 2-substituted allyl chlorides
作者:Yuh-Wern Wu、Hsu-Ting Huang、Zhau-Jie Huang、Huang-Ming Huang、Jyh-Ferng Yang
DOI:10.1016/j.tet.2005.02.083
日期:2005.5
values of free radical SH2′ reactions have been determined in various solvents. The correlation of Hammett ρ with Taft's π* gives a W value of 0.70. The W value is a measure of susceptibility of the reaction constant to change in solvent polarity. However, the W value is 2.64 in the dissociation reactions of substituted benzoic acids. The free radical reactions are less susceptible to the solvent effect
自由基S H 2'反应的ρ值已在各种溶剂中确定。哈米特的相关ρ与塔夫脱的π*给出了一个W¯¯的0.70值。该w ^值是反应常数在溶剂极性变化的敏感性的量度。但是,在取代的苯甲酸的离解反应中,W值为2.64。自由基反应比离子反应更不易受溶剂作用的影响,这可以合理化,因为在自由基反应的过渡态中形成的部分电荷小于杂合反应的部分电荷。S H中的ρ值2'反应可能无法真正反映过渡态下的部分电荷分离,但是,它可能是反应对替代物电子效应的敏感性的量度。