Why Lewis Acids Control This Reaction #organicchemistry #mechanism

Added: 2026-05-19

[00:00:00]Friedel-Crafts alkylation is a nifty reaction that allows us to take an aromatic compound and add an alkyl group to it. Mechanistically speaking, we'll start by making a complex between our alkyl halide and our catalyst, aluminum chloride in this case, looking like this, which will then lose the chlorine making a corresponding carbocationic species, which is going to be our electrophile. Now, once we have our electrophile, we're going to react it with our aromatic compound, which is going to be a nucleophile in this interaction, giving us a corresponding resonance-stabilized carbocationic intermediate, which is sometimes referred to as a sigma complex. And finally, we're going to deprotonate our carbocation, restoring our aromaticity in the aromatic ring, and giving us our final product. Easy peasy.