# Why can an anti-markovnikov radical addition of haloalkane only happen in presence of hydrogen peroxide?

Jun 13, 2015

In a "normal" Markovnikov attrition of $\text{HBr}$ to an alkene, the $\text{H}$ adds to the carbon with more hydrogen atoms in order to form the more stable carbocation.

#### Explanation:

In the peroxide-catalyzed addition, the bromine radical adds to the carbon with more hydrogen atoms in order to form the more stable radical.

That means that the $\text{H}$ must go on the carbon with fewer $\text{H}$ atoms.