The Friedel-Crafts alkylation is an organic reaction used to convert an aryl compound and an alkyl halide to a substituted aromatic compound using a Lewis acid catalyst (such as AlCl3). The reaction begins with the Lewis acid abstracting the halide from the alkyl halide to form an electrophilic alkyl cation and a tetrasubstituted aluminum anion. The aromatic compound then attacks the alkyl cation via an electrophilic aromatic substitution (SEAr) to give a cationic product with loss of aromaticity. Deprotonation with the aluminum anion results in the final aromatic product and regeneration of the Lewis acid catalyst.
Crafts, J. M.; Friedel, C. J. Chem. Soc. 1877, 32, 725–725.