Question

Account for the following: Aniline does not undergo Friedel-crafts reaction?

Answer 1

Friedel-crafts reaction:

• A Friedel-Crafts reaction is known as an organic coupling reaction which basically involves an electrophilic aromatic substitution used for the attachment of substituents to the aromatic rings.
• The two important types of Friedel-Crafts reactions are the Friedel-Crafts alkylation and Acylation reactions.

Aniline does not undergo Friedel-crafts reaction:

• Aniline does not usually undergo Friedel craft's reactions because the reagent used in the reaction i.e ${\mathrm{AlCl}}_3$(usually used as a Lewis acid catalyst ) is electron deficient in nature and hence acts as a Lewis base.
• This lewis base attacks on the lone pair of nitrogen atoms present in the aniline forming an insoluble complex which precipitates out and the reaction do not proceed further.
• The positive charge formed on the nitrogen atom of the aniline is strongly electron-withdrawing in nature and hence deactivates the ring for further acylation or alkylation reactions.

Hence, aniline does not undergo a Friedel-craft reaction.