Friedel–Crafts alkylation between chalcone epoxides and heteroarenes induced by triarylaminium salt

Contemporary Carbocation Chemistry: Applications in Organic Synthesis

“…117 Charge−charge repulsive effects tend to separate the positive charge centers, leading to positive charge formation at the remote site of the phenyl group (148). Nucleophilic attack at the para-position gives the arylated product (149) in good yield and regioselectivity. Remote functionalization has also been accomplished with trifluoromethyl-substituted carbodications.…”

“…Huo and Wang recently described a series of novel Friedel− Crafts reactions with chalcone epoxides. 149 Their chemistry involves generation of a distonic radical cation intermediate from oxidative ring-opening of the epoxide and subsequent nucleophilic reaction at the carbocationic center (Scheme 70).…”

Rapid Epoxidation of α,β-Unsaturated Olefin in Microdroplets without Any Catalysts

“…can be produced by means of ring opening and functional group conversion . Chalcone epoxide (α,β-epoxyketone) can be used as a component in perfume formulation and also as an intermediate in the production of flavoring substances. , Chalcones have unique structural characteristics and high synthetic utility because they are not only capable of carrying out conventional reactions of epoxides but are also susceptible to other conversions due to the existence of carbonyl groups. , In the epoxidation of unsaturated chalcones, various catalysts including small organic molecules, Schiff base complexes, phase transfer catalysts (PTCs), and phosphotungstic acid quaternary ammonium salts have been reported, where hydrogen peroxide, hypochlorite, and organic peroxides were used as the oxidizing agents. Phase transfer catalysis is a special type of heterogeneous catalysis that facilitates the transfer of one reactant to a phase containing another reactant to initiate the reaction.…”

Triphenylphosphine-m-sulfonate/Carbon Tetrabromide as an Efficient and Easily Recoverable Catalyst System for Friedel–Crafts Alkylation of Indoles with Carbonyl Compounds or Acetals

“…Friedel–Crafts (FC) reaction is one of the cornerstone reactions for carbon–carbon bond construction and has been widely used to generate important classes of building blocks. − However, the methods often suffer from drastic reaction conditions and more than stoichiometric amounts of catalysts. With the recent increased environmental and economic awareness, the development of greener and/or sustainable methods for this fundamental transformation has emerged in recent years. − …”