Friedel‐Crafts Reactions

Abstract

After the initial discovery by Friedel and his American associate, James Mason Crafts, that anhydrous aluminum chloride could be used as a condensing agent in a general synthetic method for furnishing an infinite number of hydrocarbons. They extended their discoveries of the catalytic effect of aluminum chloride in a variety of organic reactions: (1) reactions of alkyl and acyl halides and unsaturated compounds with aromatic and aliphatic hydrocarbons; (2) reactions of acid anhydrides with aromatic hydrocarbons; (3) reactions of oxygen, sulfur, sulfur dioxide, carbon dioxide, and phosgene with aromatic hydrocarbons; (4) cracking of aliphatic and aromatic hydrocarbons; and (5) polymerization of unsaturated hydrocarbons. The diversity of reactions is astounding. Many important industrial processes such as the production of high octane gasoline, ethylbenzene (eventually leading to polystyrene), synthetic rubber, plastics, and detergent alkylates are based on Friedel‐Crafts chemistry. Friedel‐Crafts‐type reactions are generally considered to be any substitution, isomerization, elimination, cracking, polymerization, or addition reaction that takes place under the catalytic effect of Lewis acid‐type acidic halides (with or without cocatalysts) or Brønsted acids. Friedel‐Crafts reactions can be divided into two general categories: alkylations and acylations. Within these two broad areas there is considerable diversity. Friedel‐Crafts catalysts are electron acceptors, ie, Lewis acids. Catalysts include acid halides (Lewis acids), metal alkyls and alkoxides, protic acids (Brønsted Acids), acidic oxides and sulfides (acidic chalcogenides), acidic cation‐exchange resins, and superacids (Brønsted superacids, super Lewis acids, Brønsted‐Lewis superacids, solid superacids, and superacidic zeolites).

Quinazolin-4(3H)-ones: A Tangible Synthesis Protocol via an Oxidative Olefin Bond Cleavage Using Metal-Catalyst Free Conditions

“…Oxidative cleavage of unsaturated hydrocarbons is one of the most significant and efficient approaches to produce carbonyl compounds in organic chemistry, petrochemical industry as well as the conversion of biomass [1][2][3][4]. Aldehydes and ketones are important precursors to acids and alcohols as well as widely used in pharmaceutical, agriculture and most importantly in the fine chemical industry.…”

Dicarboxylic Acid‐Functionalized MCM‐41 with Embedded Palladium Nanoparticles as an Efficient Heterogeneous Catalyst for C–C Coupling Reactions

“…Lewis acid catalyzed Friedel-crafts acylation is a traditional method for the synthesis of aromatic ketones which has disadvantage such as regioselectivity and failure with electron-deficient arenes. [8] The reaction of acyl halides and organometallic reagents such as Grignard reagents, organo-zinc, cadmium, and copper is a convenient strategy for the for the preparation of ketones. Due to the addition of an organometallic reagent to the ketone, alcohol production is a problem.…”

Microwave-assisted hydroarylation of styrenes catalysed by transition metal oxide nanoparticles supported on mesoporous aluminosilicates

“…In general, Friedel-Crafts alkylations and acylations are one of the most powerful methods for Carbon Carbon bond-forming reactions [2][3][4]. These reactions have been traditionally performed using strong Lewis acids including TiCl 4 , BF 3 ·OEt 2 , and AlCl 3 as well as mineral acids such as HF and H 2 SO 4 .…”