[davidenarb]

Hi all,

I would like to understand why this reaction cannot occur. I know that the nitro group is a strong deactivator, but normally, the raction can take place at the meta position ! so why it cannot?

[Hunter2]

Who says it doesnt work?

[davidenarb]

Who says it doesnt work?

The textbook

[Hunter2]

It doesnt give you an explanation?

[davidenarb]

It says that strong and moderate deactivators are not compatible with Friedel Crafts Alkylation, but why?

[puffincatz23]

Friedel Crafts Alkylation reactions, being a subclass of electrophilic aromatic substitution, involves the aromatic ring acting as a nucleophile. For this particular reaction, though, the nucleophile is severely crippled by the nitro group, as it is a strong electron withdrawing group/deactivator like you said. Therefore, the nucleophile is not strong enough to attack the alkyl chlorine-aluminum trichloride adduct. Hope this helps?

[zsinger]

Rigorously speaking, The bond between the Carbon and Chlorine is not weakened enough by the adduct formed with AlCl3 to allow electron density into that region in space.  You can get much more into quantum arguments, but that is the reason in a nutshell if I'm not mistaken.
             -Zack