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We know that phenol and aniline, despite being strongly activating, are unable to to undergo Friedel-Crafts reactions because they form complexes with $\ce{AlCl3}$, thanks to the lone pair on nitrogen and oxygen atoms.

However, according to my notes (and Google) anisole does undergo Friedel-Crafts reactions. How can it be possible, why is there no complex formation this time?

Also, I wanted to know how can we say that a certain group like $\ce{OH}$ will surely form a complex? Is containing a lone pair a sufficient condition?

Sawarnik
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  • What complex does it form? – Yashas Apr 08 '17 at 02:59
  • @Yashas For eg, phenol forms Ar-(OH+)-(AlCl3-) – Sawarnik Apr 08 '17 at 04:20
  • Not sure if this correct, but you could use alkyl triflate, instead of alkyl chloride + $\ce{AlCl3}$. Triflate is a good leaving group and can generate carbocations with easily react with the activated ring of phenol or aniline. – Pritt says Reinstate Monica Apr 22 '17 at 04:27
  • Completely a duplicate of https://chemistry.stackexchange.com/questions/31531/friedel-crafts-reaction-of-phenol/31548#31548 –  Feb 07 '24 at 05:08
  • Completely a duplicate of https://chemistry.stackexchange.com/questions/72184/friedel-crafts-reaction-of-anisole#autocomment382586 –  Feb 07 '24 at 05:10
  • https://chemistry.stackexchange.com/questions/72184/friedel-crafts-reaction-of-anisole#autocomment382587 –  Feb 07 '24 at 05:12

1 Answers1

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Friedel-Crafts acylation of anisole with acetyl chloride and aluminium chloride as catalyst is a standard laboratory procedure to synthesize acetanisole.

            source: Wikipedia, user Jü

The fact that this reaction is possible does not imply that there is no complex formation with $\ce{AlCl3}$. On the contrary, it is quite probable that such complexes do form due to the interaction of the methoxy oxygen with $\ce{AlCl3}$.

Therefore, and to compensate the formation of complexes with the resulting ketone, $\ce{AlCl3}$ is added in more than two-fold excess in the above synthesis.

aventurin
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