[Allendo]

Hi Team
I have a reactant 1-methylcyclohex-1-ene with 2 different reaction.
1. light and Br2 (or NBS)
2. HBr and ROOR.
The reaction is drawn in the attachment. I apologize for my writing.

Both methods creates the same Bromine radicals at the initiation step. However, one radical attack the allylic position but the other attack the double bound. Can anyone help me explain why? Is it because the second reaction creat less Br radical than the first reaction?

Thanks
Allen

[hollytara]

The same intermediate (bromine atom) and substrate ought to give the same product - is this from the literature?

[Allendo]

Thanks for reply.
Yes I believe it is from literature. If google these reaction online, I found the results of these 2 reactions in agreement with what I wrote...

[sjb]

The same intermediate (bromine atom) and substrate ought to give the same product

True but is this the same; solvent, temperature, byproducts etc?

[Babcock_Hall]

IIRC NBS gives a low concentration of Br₂, although how this affects the distribution of products is not clear to me.