O-Chem reactions.........C=C-C-C + HBr/ROOR-Hv ----> ?

[Toothguy80]

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Ok, so if you have C=C-C-C + HBr with the solvent being ROOR or light, is it AntiMarkovnikov?

Kaplan is driving me nuts

Someone please explain?

 

[bkim]

Ok, so if you have C=C-C-C + HBr with the solvent being ROOR or light, is it AntiMarkovnikov?

Kaplan is driving me nuts

Someone please explain?

yeah it is anti-mark. The Br radical will first attack the double bond and will stick to the first carbon (this is make the second carbon a radical). Only after then will the H radical bond with the second carbon.

 

[laundry]

You will get a Br-C-C-C-C because you have to form a more stable free radical ( 1 < 2 < 3 ).

Unlike a electrophilic halogenation, where the H attacks first across a double bond, forming a more stable carbocation, which is then attacked by the Br-.

Hope this helps

 

[levyusupov]

you also nedd to know the two most important steps in this reaction:

the first step: called the initiation step, where Br2 splits to 2Br radicals

and

the last step: called the termination where there is collision between two radicals.