whawha

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If ethylbenzene is treated with Br2/uv, we get a bromine on the benzylic carbon, right?

If it is treated with NBS, ROOR and heat, aren't we supposed to have the bromine on the second carbon (btw, what is that carbon called?)

I remember a question where it was saying, NBS,ROOR would attach bromine to allylic position, say if you have a cyclohexene.

Am i missing something?
 

vlct0ria

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If ethylbenzene is treated with Br2/uv, we get a bromine on the benzylic carbon, right?

If it is treated with NBS, ROOR and heat, aren't we supposed to have the bromine on the second carbon (btw, what is that carbon called?)

I remember a question where it was saying, NBS,ROOR would attach bromine to allylic position, say if you have a cyclohexene.

Am i missing something?
As I recall, NBS/ROOR will attach Br to the benzyllic carbon just like Br2/hv.
 

vlct0ria

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But, if you have peroxide, doesn't it normally follow Anti-markovnikov rule? So, bromine attached on less stable carbocation, which is C2 in the compound above?
I think the peroxides are just added as initiators for free radical bromination. Pretty much whenever you see NBS with alkyl benzenes, Br is selectively substituted at the benzyllic carbon.
 

vlct0ria

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What about simple alkene? It will be anti-markov, right?
If you're still talking about NBS/ROOR, bromination then occurs at the allylic C...Markovnikov's isn't relevant.
 

alanan84

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And, HBR/ROOR and NBS/ROOR do the same thing, right? Thank you again :)
I don't think they do the same thing.

HBr/ROOR adds Br anti-markovnikov and NBS/ROOR will add it to the allylic carbon...

Right?