Why doesn’t aniline undergo Friedel-Crafts alkylation?

Even though aniline is an activated benzene derivative, it still doesn’t undergo Friedel-Crafts alkylation. Why?


Can it undergo Friedel-Crafts acylation?




The answer lies in the fact that aniline is a Lewis base and $\ce{AlCl3}$ is a Lewis acid. The reaction between aniline and $\ce{AlCl3}$ hampers the catalytic activity of $\ce{AlCl3}$ required to perform the Friedel-Crafts alkylation and acylation.



> 
> Despite the activation of the $\ce{NH2}$ group, Friedel-Crafts alkylations and acylations fail because the $\ce{NH2}$ group acts as Lewis base and interacts with the Lewis acid catalyst. ... A way to overcome this problem is to convert the $\ce{NH2}$ group into an amido group prior to Friedel-Crafts reaction. ...The amide group can be hydrolysed back to aniline group after alkylation.
> 
> 
> (Pg. 1167 An Introduction to Organic, Inorganic and Physical Chemistry. 4th edition. Catherine E. Housecroft, Edwin C. Constable. Pearson Education Limited)
> 
> 
> 


The aniline forms a Lewis acid base adduct with $\ce{AlCl3}$ :[![adduct](https://i.stack.imgur.com/4z0Xkm.png)](https://i.stack.imgur.com/4z0Xkm.png)


This prevents the interaction between alkyl or acyl chloride with $\ce{AlCl3}$.


 13