Markovnikov vs Anti-Markovnikov — Comparison Note — Notes | NoteTube

Feature	Markovnikov Addition	Anti-Markovnikov (Kharasch)
Conditions	No peroxide; acidic/ionic	HBr + organic peroxide (ROOR) ONLY
Mechanism	Electrophilic (ionic)	Free radical (chain reaction)
Which HX works?	HF, HCl, HBr, HI, $H_{2}O$	ONLY HBr (not HCl, not HI)
First species to add	$H^{+}$ (electrophile)	Br• (radical)
Site of H addition	C with more H atoms	C with fewer H atoms
Intermediate	More stable carbocation	More stable carbon radical
Product from propene	2-Bromopropane `CC(Br)C`	1-Bromopropane `CCCBr`
Driving force	Carbocation stability	Radical stability
Why not HCl + peroxide?	N/A	Cl• + alkene is endothermic — chain fails
Why not HI + peroxide?	N/A	I• too reactive — premature termination

Markovnikov (propene + HBr, no peroxide):

CC=C --[HBr, no peroxide]--> CC(Br)C (2-bromopropane)

Mechanism: $H^{+}$ → secondary carbocation (C-2) → $Br^{-}$ attacks C-2

Anti-Markovnikov (propene + HBr + ROOR):

CC=C --[HBr, ROOR]--> CCCBr (1-bromopropane)

Mechanism: ROOR → RO• → Br• → adds to C-1 (less substituted) → 2° radical at C-2 → H from HBr → 1-bromopropane