free radicals

homolytic cleavage

sigma bond splits in half resulting in two radicals

addition to pi bond

radical added to pi bond, breaks pi bond and radical added

hydrogen abstraction

hydrogen detaches from compound and attaches to radical; compound is now a radical

halogen abstraction

halogen detaches from compound and attaches to radical; OG compound becomes radical

Elimination

opposite of addition to pi bond; single bond btw radical (alpha) and adjacent carbon (beta) becomes double bond; radical is changed to halogen

coupling

opposite of cleavage, two radicals combine via lone electrons pairing

initiation

radicals are formed via cleavage

propagation

radicals are transferred

termination

radicals are combined via coupling

radical inhibitors (2)

hydroquinone, O2

chlorination/bromination is more selective

bromination

chiral halogenation with chlorination/bromination prefers ___ stereochemistry

racemic

lowest BDE

benzylic/allylic

Highest BDE

Methyl//primary

reagent used for radical bromination instead of ionic bromination

NBS- allows less concentration of bromine