推拉效应指的是当自由基中心碳原子同时连有推电子基与吸电子基时,该自由基特别稳定的一种现象。反应中如涉及这种自由基,反应的速度、选择性,产率及机理等皆会有变化。因此近年来,人们对此呈现很大的兴趣。 最早从理论上研究多取代自由基稳定性的是Dewar,后来Balaban观察了许多有关 Push-pull effect refers to the center of the free radical when the carbon atoms are simultaneously pushed electron-withdrawing electron-withdrawing group, the free radical is a particularly stable phenomenon. If the reaction involves such free radicals, the reaction speed, selectivity, yield and mechanism will change. So in recent years, people have shown great interest in it. The earliest theory to study the stability of more than substitute for free radical Dewar, Balaban later observed a lot about