Knowra Friedel–Crafts acylation Friedel–Crafts acylation Friedel–Crafts acylation replaces a hydrogen on an aromatic ring with an acyl group through electrophilic aromatic substitution, commonly using an acyl halide and a Lewis acid.
Acylium ion : A resonance-stabilized ion with the structure RCO⁺ that acts as an electrophile in many acylation reactions. A Lewis acid promotes its formation from an acyl halide, enabling attack on the aromatic ring.
Aromatic ketone : A ketone whose carbonyl carbon is directly bonded to an aromatic ring. This is the characteristic product when an acyl group replaces an aromatic hydrogen.
Friedel–Crafts alkylation : An electrophilic aromatic substitution that installs an alkyl group, commonly using an alkyl halide and a Lewis acid. Alkylation can rearrange its electrophile and cause repeated substitution; acylation generally avoids both problems.
Acyl halide : A carboxylic acid derivative in which the hydroxyl group is replaced by a halogen, with formula RCOX. Acyl halides are common acyl-group donors in this reaction.
Charles Friedel : A French chemist whose work with James Crafts included the reactions that bear their names. Friedel co-developed the acylation alongside Crafts in the nineteenth century.
Electrophilic aromatic substitution : A reaction class in which an electrophile replaces a hydrogen on an aromatic ring while aromaticity is restored. Acylation follows this general mechanism, including formation and loss of a sigma complex.
Acetylation : The introduction of an acetyl group, CH₃CO–, into a molecule. Acetylation is a widely used form of Friedel–Crafts acylation that produces aryl methyl ketones.
Gattermann–Koch reaction : A formylation that introduces a formyl group onto an aromatic ring using carbon monoxide, hydrogen chloride, and catalysts. It installs an aldehyde group, unlike acylation with ordinary acyl halides, which gives ketones.
Lewis acid : An electron-pair acceptor that forms a bond by accepting a pair of electrons from a donor. Lewis acids activate acyl halides and influence the reaction’s required conditions.
James Crafts : An American chemist known for research on organic reactions and for co-developing Friedel–Crafts reactions. Crafts collaborated with Friedel on the reactions’ early development.
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