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Reaction conditions are similar to the Friedel–Crafts alkylation. This reaction has several advantages over the alkylation reaction. Due to the electron-withdrawing effect of the carbonyl group, the ketone product is always less reactive than the original molecule, so multiple acylations do not occur.
Clemmensen reduction conditions are particularly effective at reducing aryl [4]-alkyl ketones, [5] [6] such as those formed in a Friedel-Crafts acylation. The two-step sequence of Friedel-Crafts acylation followed by Clemmensen reduction constitutes a classical strategy for the primary alkylation of arenes.
Here, a strong Lewis acid is required to generate either a carbocation from an alkyl halide in the Friedel-Crafts alkylation reaction or an acylium ion from an acyl halide. In the vast majority of cases, reactions that involve leaving group activation generate a cation in a separate step, before either nucleophilic attack or elimination.
Alkylation is a chemical reaction that entails transfer of an alkyl group. The alkyl group may be transferred as an alkyl carbocation , a free radical , a carbanion , or a carbene (or their equivalents).
Cumene is formed in the gas-phase Friedel–Crafts alkylation of benzene by propene. Benzene and propene are compressed together to a pressure of 30 standard atmospheres at 250 °C in presence of a catalytic Lewis acid. Phosphoric acid is often favored over aluminium halides.
Friedel-Crafts alkylation: alkylbenzenes can be synthesized from olefins or alkyl halides with aromatic compounds in the presence of a catalyst such as AlCl 3, HF, or H 2 SO 4. [ 4 ] Gattermann-Koch reaction : named after German chemists Ludwig Gattermann and Julius Arnold Koch , the Gattermann-Koch reaction is a catalyzed formylation of ...
To synthesize coumarin derivatives, β-ketoesters can be condensed with phenols under acidic conditions. [3] In this case, a transesterification reaction occurs first with the formation of the phenol ester. This is then followed by ring closure, similar to Friedel-Crafts alkylation.
Frankland–Duppa reaction; Fráter–Seebach alkylation; Free radical halogenation; Freund reaction; Friedel–Crafts acylation; Friedel–Crafts alkylation; Friedländer synthesis; Fries rearrangement; Fritsch–Buttenberg–Wiechell rearrangement; Fujimoto–Belleau reaction; Fujiwara–Moritani reaction; Fukuyama coupling; Fukuyama indole ...