Friedel Crafts Acylation
Friedel Crafts Acylation - Related Videos
01:11
Electrophilic Aromatic Substitution: Friedel–Crafts Acylation of Benzene
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2025
The Friedel–Crafts acylation reactions involve the addition of an acyl group to an aromatic ring. These reactions proceed via electrophilic aromatic substitution by employing an acyl chloride and a Lewis acid catalyst such as aluminum chloride to form aryl ketone. The mechanism involves the formation of a complex between the Lewis acid and the acyl chloride. An acylium ion is formed by the cleavage of the carbon-chlorine bond of the complex. The acylium ion has a positive charge on the carbon...
01:26
Limitations of Friedel–Crafts Reactions
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2025
Several restrictions limit the use of Friedel–Crafts reactions. First, the halogen in the alkyl halide must be attached to an sp3-hybridized carbon for the Friedel–Crafts reactions to occur. Vinyl or aryl halides do not react since the carbocations formed are unstable under the reaction conditions. Second, Friedel–Crafts alkylation is susceptible to carbocation rearrangement, and the major products obtained have a rearranged carbon skeleton. In contrast, the acylium ion is stabilized by...
01:17
Electrophilic Aromatic Substitution: Friedel–Crafts Alkylation of Benzene
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2023
Friedel–Crafts reactions were developed in 1877 by the French chemist Charles Friedel and the American chemist James Crafts. Friedel–Crafts alkylation refers to the replacement of an aromatic proton with an alkyl group via electrophilic aromatic substitution. A Lewis acid catalyst such as aluminum chloride reacts with an alkyl halide to form a carbocation. The resulting carbocation then reacts with the aromatic ring and undergoes a series of electron rearrangements before giving the final...
09:58
Metal-free Synthesis of Ynones from Acyl Chlorides and Potassium Alkynyltrifluoroborate Salts
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Cited by 3 •
2015
The goal of this manuscript is to demonstrate a straightforward method for the preparation of ynones from acyl chloride and potassium alkynyltrifluoroborate salt starting materials. The one-pot reaction proceeds rapidly in the presence of boron trichloride without exclusion of air and moisture.
08:31
Detection of Protein S-Acylation using Acyl-Resin Assisted Capture
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Cited by 29 •
2020
Acyl-RAC (Acyl-Resin Assisted Capture) is a highly sensitive, reliable and easy to perform method to detect reversible lipid modification of cysteine residues (S-acylation) in a variety of biological samples.
FAQs
Aluminum chloride acts as a Lewis acid, meaning it activates the acyl chloride or acid anhydride used as the acyl-group source. This activation generates the reactive acylium ion needed for attack on the aromatic ring. Its role therefore connects the starting acylating reagent to the electrophilic step that ultimately produces the aryl ketone.
After the acylium ion attacks the electron-rich aromatic ring, the ring temporarily loses its aromatic character. Deprotonation removes a hydrogen from the attacked site, restoring aromaticity and yielding the substituted aryl ketone framework. This sequence explains why electrophilic attack and proton loss are both essential parts of the reaction mechanism.
The aromatic ring serves as the site of electrophilic attack, and its electron-rich character supports reaction with the acylium ion. Because the acyl group is introduced through this attack, the ring's participation determines where the new carbon-carbon bond forms. Subsequent deprotonation converts the attacked intermediate into an aromatic product.
Hydrolysis releases the ketone product after the aromatic substitution sequence has occurred. Before this step, the acyl group has been introduced through electrophilic attack and deprotonation, but hydrolysis has not yet released the ketone. Thus, hydrolysis completes conversion to the aryl ketone used for subsequent chemistry.
A typical reaction combines an aromatic ring with an acyl chloride or acid anhydride in the presence of a Lewis acid such as aluminum chloride. The Lewis acid activates the acylating reagent, while the aromatic substrate supplies the electron-rich ring. Hydrolysis follows the substitution sequence to release the aryl ketone product.
Friedel Crafts acylation provides a controlled way to construct a carbon-carbon bond between an aromatic ring and an acyl-derived fragment. The resulting aryl ketone is also a functionalized aromatic compound that can serve as an intermediate for further organic transformations. This makes the reaction useful in synthetic sequences requiring additional chemical modification.
It is used to synthesize functionalized aromatic compounds and aryl ketones relevant to several product areas. The applications include pharmaceuticals, fragrances, dyes, and intermediates for further organic transformations. Its value in these settings comes from introducing an acyl group while forming a carbon-carbon bond, creating aromatic products that can support later synthetic steps.