It is an accepted principle that the inductive effects of halogen substituents reduces the reactivity of hydrogen to radical abstraction by chlorine'-, or bromine atoms. 4 Furthermore it is accepted that resonance effects of halogen substituents have an effect on geminal- hydrogen reactivity that is opposite that of their inductive effect^.^ Copp and Tedder have shown that substitution of hydrogen by chlorine lowers the activation energy for radical ...
