20.8 : 라디칼 반응성: 개요

The unpaired electron makes radicals a highly reactive species.

Consequently, radicals undergo three forms of reactions to achieve stability:

first, by combining with another radical and forming a spin‐paired molecule;

second, by reacting with another spin‐paired molecule to generate a new radical and a new spin‐paired molecule;

third, by decomposing in a unimolecular reaction to form a new radical and a spin‐paired molecule.

These three possible reactions lead to six common steps in radical mechanisms: homolysis, addition to a π bond, hydrogen abstraction, halogen abstraction, elimination, and coupling.

These steps can be categorized into the initiation, propagation, and termination stages of a typical radical mechanism.

Generally, radical reactivity is governed by steric hindrance and electronic stabilization, with electron‐donating and withdrawing groups making radicals nucleophilic and electrophilic, respectively.