> See also: > - [[Chemical Reactions]] # Radical Reactions ## Resonance Structures of Radicals A [[Allylic and Vinylic Positions|vinylic]] radical is not resonance stabilized and does not have a resonance structure ### Stability of Radicals Radicals exhibit a similar behavior as the [[stability of carbocations]] ![[Stability of Carbocations.png|400]] ## Radical Inhibitors A **radical inhibitor** is a compound that prevents a radical chain process from either getting started or continuing. - *Anti-oxidants (such as Vitamin E & C) are common examples of radical inhibitors within our bodies* ## Radical Scavengers [[Radical Reactions]] are always formed through an initial [[Chemical Bond Cleavage|homolytic cleavage]]. ## Steps & Mechanisms of Radical Reactions > "As long as radicals exist, the reaction will continue through the propagation stage until the radicals disperse." 1. **Initiation:** The radicals are created 2. **Propagation:** The location of the unpaired electron is moved around 3. **Termination:** The radicals are 'annihilated' by forming a bond ![[Common Radical Reaction Mechanisms.png]] > [!info]+ Mechanisms of Radical Reactions > Each of the four main propagation mechanisms contain **three fishhook arrows.** > > 1. **[[Chemical Bond Cleavage|Homolytic Cleavage]]** > - splitting a sigma bond to form two radicals > - aka Initiation > 2. **Addition to a $\pi$ bond** > - shifting radical to adjoining atom > > --- > > 3. **Hydrogen Abstraction** > - a > 4. **Halogen Abstraction** > - a > > --- > > 5. **Elimination** > - a > 6. **Coupling** > - (aka Termination) - While there are the four radical reaction mechanics that are most common in the propagation phase, the initiation and termination stages can sometimes contain multi-step reactions with several propagation steps inbetween. ## Common Behaviors of Radical Reactions **Selectivity of Halogenation** Chlorination vs Bromination - Chlorination is fast and unselective - Bromination is slow and selective ### Common Reagents in Radical Reactions ![[Radical Reaction Reagents.png]] - [ ] subs