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Leslie Coduti

Free radical bromination at benzylic positon

David Duryee  Follow
The benzylic radical and the benzylic cation also are quite stable, and with the correct substituents they can be isolated.
The resonance contribution, as you have shown, from the other radicals is small as you correctly say addition there will initially destroy the aromatic system. If you do this reaction on a large enough scale (kg) you can sometimes see the ring brominated products in very small quantities (<0.5%).

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Barbara Mckeon  Follow
You need something that can form a radical. If it's like t-Butylbenzene then you won't get benzylic bromination.
But you may form other radicals which can re-arrange to give a multitude of products.

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Connor Becz  Follow
Quote from:
The benzylic radical and the benzylic cation also are quite stable, and with the correct substituents they can be isolated.
The resonance contribution, as you have shown, from the other radicals is small as you correctly say addition there will initially destroy the aromatic system. If you do this reaction on a large enough scale (kg) you can sometimes see the ring brominated products in very small quantities (<0.5%).

Thank you for your confirmation!!!

Just to ask another quick question: the bromination won't occur if the benzylic position doesn't have any proton, correct?

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Beheruz N Sethna  Follow
Quote from:
You need something that can form a radical. If it's like t-Butylbenzene then you won't get benzylic bromination.
But you may form other radicals which can re-arrange to give a multitude of products.

Thank you very much :)

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