Naked Science Forum

Non Life Sciences => Chemistry => Topic started by: aysha on 06/08/2009 11:27:48

Title: Why do bromine radicals react in a highly specific manner with alkenes?
Post by: aysha on 06/08/2009 11:27:48

Why does a Br• radical add to the alkene with characteristic regioselectivity, giving a primary alkyl bromide when the polar addition of HBr to an alkene would give a tertiary alkyl bromide? (1) attack at the unsubstituted end of the alkene is less sterically hindered; and (2) the tertiary radical thus formed is more stable than a primary radical.

In fact, of all the hydrogen halides, only HBr will add to alkenes in this fashion: HCl and HI will undergo only polar addition to give the tertiary alkyl halide.

But why?

Title: Re: Why do bromine radicals react in a highly specific manner with alkenes?
Post by: Bored chemist on 06/08/2009 18:40:32

Good question. Do you have any thoughts on the matter?