July 07, 2020, 10:42:40 AM
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Topic: Leaving Groups & Nucleophilic Aromatic Substitution  (Read 21719 times)

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Offline wilson

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Re: Leaving Groups & Nucleophilic Aromatic Substitution
« Reply #15 on: March 09, 2007, 11:36:45 PM »
Conclusively, if i were to chlorinate m-nitrochlorobenzene, I will get 1,2,3-nitrodichlorobenzene. Yes?

Offline english

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Re: Leaving Groups & Nucleophilic Aromatic Substitution
« Reply #16 on: March 10, 2007, 01:40:25 PM »
Well chlorination of m-chloronitrobenzene would be a SNAr reaction because a chloride would just replace another chloride, which would give you the same beginning product.  But as you can see this is silly to comment on.

You would have an electrophilic substitution reaction as well, which actually involves some change.  In this case since nitro is strongly deactivating, you would need a Lewis acid, i.e. ferric chloride.

The competing para, ortho and meta positions would result due to the two differing substituents.  However, nitro is more strongly deactivating than Cl, so more product would result from chlorine being at the meta position of nitro.

You would have 1,3-dichloro-5-nitrobenzene.   It must be remembered that the other positions can be occupied, but the 3 position would be moreso.
« Last Edit: March 10, 2007, 02:20:34 PM by g english »

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