The Friedel–Crafts reactions are a set of reactions developed by Charles Friedel and James Crafts in 1877 to attach substituents to an aromatic ring.^[1] There are two main types of Friedel–Crafts reactions: alkylation reactions and acylation reactions, both proceeding by electrophilic aromatic substitution. The general reaction scheme is shown below.

^{Friedel–Crafts alkylation involves the alkylation of an aromatic ring with an alkyl halide using a strong Lewis acid catalyst. With anhydrous ferric chloride as a catalyst, the alkyl group attaches at the former site of the chloride ion. The general mechanism is shown below.[6]}

Friedel–Crafts alkylation