Free radical addition is an exception to this rule
Free radical addition is an exception to this rule, which always produces regioselective reactions. The addition of a peroxide also prevents this rule from applying, and the formation of a carbocation intermediate is an important step in another reaction which violates this rule. That reaction is hydroboration, which proceeds according to the anti version of this rule. For ten points, idetnify this rule, the reverse of Zaitsev's rule, which states that when a protic acid is added to an alkene, the hydrogen atom gets attached to the carbon atom with the greatest number of hydrogens.
Free radical addition is an exception to this rule, which always produces regioselective reactions.