9.1.2.2 Addition
Free radicals undergo addition to carbon-carbon double bonds. The reaction is generally selective. For example, addition to CH2=CHX takes place exclusively at the methyl group, irrespective of the nature of X.
Alkynes also exhibit similar reactivity with free radicals.
9.1.2.3 Combination and Disproportionation
Two free radicals can combine by dimerization or disproportionation.
These reactions are generally fast, some having negligible activation energies.
9.1.2.4 Rearrangement
Free radicals are known to rearrange in certain circumstances. For example, the addition of free radical leads to rearrangement due to relief of strain in the cyclic system.
