Catalyzed Friedel-Crafts Alkylation Research Articles

Chiral Brønsted acid catalyzed Friedel–Crafts alkylation reactions

The asymmetric Friedel-Crafts reaction is one of the most powerful methods to synthesize optically active aromatic compounds. Particularly, the Friedel-Crafts alkylation of arenes with unsaturated compounds activated by chiral Brønsted acids provides direct access to enantiopure aromatic derivatives with perfect atom economy. In this tutorial review, recent progress in the development of chiral Brønsted acid-catalyzed asymmetric Friedel-Crafts reactions is presented.

A Novel Synthetic Route to 2-Arylalkanoic Acids by a Ruthenium-Catalyzed Chemoselective Oxidation of Furan Rings

An efficient two-step synthesis of 2-arylalkanoic acids from 1-arylalkanols is described. Firstly, 1-arylalkylfuran derivatives were synthesized in high yields by the metal triflate catalyzed Friedel-Crafts alkylation of 2-methylfuran with 1-arylalkanols without employing anhydrous conditions. The chemoselective oxidation of the furan ring in 1-arylalkylfurans to carboxylic acid was then investigated. In a solvent system of hexane-EtOAc/H 2 O (1:3:4), the furan ring was selectively oxidized with 7 equivalents of NaIO 4 by using 0.5 mol% RuCl 3 as catalyst to give 2-arylalkanoic acids in good yields. The selectivity of ruthenium oxidation was controlled by the solvent ratio of hexane-EtOAc.

Concise Stereoselective Synthesis of (−)‐Podophyllotoxin by an Intermolecular Iron(III)‐Catalyzed Friedel–Crafts Alkylation

Without further ado, the building blocks 1–3 were combined in three CC bond-forming reactions to provide the enantiomerically pure natural product (−)-podophyllotoxin (4). The stereogenic center at C1 was generated in the key reaction, a diastereoselective iron(III)-catalyzed intermolecular Friedel–Crafts alkylation.

Silica Sulfuric Acid–Catalyzed Friedel–Crafts Alkylation of Indoles with Nitro Olefins

The 1,4‐conjugate addition of indoles to nitro olefins was efficiently carried out using an environmentally benign catalyst, silica sulfuric acid, at ambient temperature. IICT Communication No. 070512

Halogen-Promoted Catalytic Friedel-Crafts Alkylation with Alkenes

The Friedel-Crafts alkylation is one of the most common C-C bond-forming reactions. This is the first report concerning the Friedel-Crafts alkylation of arenes, using halonium ions as intermediates. This reaction gives a simple synthetic way to 1,1-diaryl-2-haloalkanes and α,α-diaryl-β-haloesters and -ketones. Substituted styrenes, cinnamic esters and halcones are suitable intermediates.

Friedel-Crafts Alkylations of Arenes with Mono- and Bis(trifluoro­methyl)oxiranes in Superacid Medium: Facile Synthesis of α-(Trifluoro­methyl)- and α,α-Bis(Trifluoromethyl)-β-Arylethanols

Triflic acid catalyzed Friedel-Crafts alkylation of aromatics with mono- and bis(trifluoromethyl)oxiranes through ring opening afforded α-(trifluoromethyl) and α,α-bis(trifluoromethyl)-β-phenylethanols in excellent yields. The regioselectivity of the ­oxirane ring opening and subsequent Friedel-Crafts alkylation have been found to depend on the electronic and steric effects of the ­substituents in the oxirane ring. DFT studies show that C2-O bond is longer than C1-O bond due to high electron-withdrawing effect of CF3 groups effecting C2-O cleavage resulting in a C2 electrophilic center promoting electrophilic substitution with the C2 center on aromatics.

Rare earth(III) perfluorooctanesulfonates catalyzed Friedel–Crafts alkylation in fluorous biphase system

The catalyst of rare earth(III) perfluorooctanesulfonates (RE(OSO 2C 8F 17) 3, RE = Sc, Y, La–Lu) were prepared from either rare earth chlorides(III) or oxides and perfluorooctanesulfonic acid. The perflates thus obtained act as novel catalysts for Friedel–Crafts alkylation in fluorous biphasic system. Perfluorohexane (C 6F 14), perfluoromethylcyclohexane (C 7F 14), perfluorotoluene (C 7F 8), perfluorooctane (C 8F 18), perfluorooctyl bromide (C 8F 17Br) and perfluorodecalin (C 10F 18, cis- and trans-mixture) can be used as fluorous solvents for this reaction. By simple separation of the fluorous phase containing only catalyst, alkylation can be repeated many times.

Continuous reactions in supercritical fluids; a cleaner, more selective synthesis of thymol in supercritical CO2

Continuous fixed-bed catalytic Friedel–Crafts alkylation of m-cresol with different alkylating agents, isopropanol (IPA) and propylene, has been carried out using supercritical CO2, scCO2, as an alternative and more environmentally friendly reaction medium, for the synthesis of the fine chemical thymol. Both a solid Lewis acid catalyst (γ-Al2O3) and a solid Bronsted acid catalyst (Nafion® SAC-13) have been investigated over a range of reaction conditions to optimise yield and selectivity for thymol. The reaction product distribution was found to be related to the type of catalyst employed. This is likely to have been due to the different reaction pathways through which the reaction occurred, a direct Friedel–Crafts alkylation in the case of Bronsted type acids and a Fries rearrangement when employing the Lewis catalyst. The new technique of 2DCOR-GC analysis was employed to establish the order of formation of the different species generated in the reaction over the two catalysts in scCO2.

Microwave Assisted Facile Synthesis of Elvirol, Curcuphenol and Sesquichamaenol Using Montmorillonite K‐10 Clay in Dry Media.

AbstractFor Abstract see ChemInform Abstract in Full Text.

The Catalytic Friedel—Crafts Alkylation Reaction of Aromatic Compounds with Benzyl or Allyl Silyl Ethers Using Cl2Si(OTf)2 or Hf(OTf)4.

AbstractFor Abstract see ChemInform Abstract in Full Text.

The catalytic Friedel–Crafts alkylation reaction of aromatic compounds with benzyl or allyl silyl ethers using Cl 2Si(OTf) 2 or Hf(OTf) 4

The Friedel–Crafts alkylation reaction of various aromatic compounds with benzyl or allyl silyl ethers is effectively promoted under mild reaction conditions using Lewis acid catalysts. A mixture of the desired phenyltolylmethanes is obtained in 80% yield from toluene with benzyl dimethylsilyl or trimethylsilyl ether at 50°C in the presence of a catalytic amount of Cl 2Si(OTf) 2 or Hf(OTf) 4.

Microwave assisted facile synthesis of Elvirol, Curcuphenol and Sesquichamaenol using Montmorillonite K-10 clay in dry media

Short, simple and convergent syntheses of the title compounds have been accomplished with good overall yields using a Montmorillonite K-10 clay catalyzed Friedel–Crafts alkylation reaction in ‘dry media’ as the key step.

Scandium(III) Triflate Catalyzed Friedel-Crafts Alkylation with Benzyl and Allyl Alcohols

Scandium(III) Triflate Catalyzed Friedel-Crafts Alkylation with Benzyl and Allyl Alcohols

Hafnium(IV) Trifluoromethanesulfonate, An Efficient Catalyst for the Friedel–Crafts Acylation and Alkylation Reactions

Abstract Hafnium(IV) trifluoromethanesulfonate (hafnium(IV) triflate, Hf(OTf)4) was synthesized from hafnium tetrachloride and trifluoromethanesulfonic acid. The triflate thus prepared was found to be effective in the catalytic Friedel–Crafts acylation reactions of various substituted benzenes with acid anhydrides in lithium perchlorate–nitromethane (LiClO4–MeNO2). Lithium perchlorate–nitromethane is an excellent solvent system, and the catalytic activity of the Lewis acid was much improved in this medium. The product was obtained in up to 250000% molar amounts based on the catalyst. Hafnium(IV) triflate was also found to be quite effective in the catalytic Friedel–Crafts alkylation reactions of aromatic compounds with alkyl chlorides. The reactions proceeded smoothly in the presence of 5% molar amount of Hf(OTf)4 and 50% molar amount of LiClO4 by using a slow addition procedure.

Perfluorooctanesulfonic Acid Catalyzed Friedel-Crafts Alkylation with Alkyl Halides

Abstract A New procedure to prepare superacid perfluorooctanesulfonic acid (POSA) is reported. POSA catalyzed Friedel-Crafts alkylation of aromatic compounds with alkyl halides in liquid-phase reactions. Alkylation gave higher total yields than the corresponding reactions with Nafion-H, without the need of any complex decomposition or work-up. The reactions do not need to be carried out under absolutely anhydrous condition. The catalyst POSA can be easily separated from the reaction mixture and reused or recovered. The reactivity of the alkylation reagents and the mechanism of the reaction are discussed.

Silica-Supported Heteropoly Acid Catalyst for Liquid-Phase Friedel–Crafts Reactions

Abstract Silica-supported Keggin-type heteropoly acids such as 12-tungstophosphoric, molybdophosphoric, and tungstosilicic acids efficiently catalyzed Friedel–Crafts alkylation and acylation reactions of aromatic hydrocarbons with 1-octene, benzyl chloride and benzoyl chloride in the liquid phase. The catalytic activity of heteropoly acid was generally enhanced when supported on silica. Silica-supported tungstosilicic acid worked as an insoluble heterogeneous catalyst even to the acylation of p-xylene with benzoyl chloride or benzoic anhydride, though deactivation was observed during repeated use. Considering that supported p-toluenesulfonic acid, an ordinarily used typical strong protonic acid, was far less active than the supported heteropoly acid, the high catalytic efficiency revealed by heteropoly acid appears to be due to a unique property of heteropoly anion which can stabilize alkyl and acyl cations as the reaction intermediates.

Heterogeneous catalysis by solid superacids: 14. Perfluorinated resinsulfonic acid (Nafion-H)-catalyzed friedel-crafts alkylation of toluene and phenol with alkyl chloroformates and oxalates

Perfluorinated resinsulfonic acid (Nafion-H)-catalyzed Friedel-Crafts alkylation of toluene and phenol with alkyl chloroformates and oxalates was studied, in both liquid- and gas-phase reactions. Alkylations gave good yields in clean reactions without the need for any complex decompositions or workup. No acylation side products were formed in the reactions. The question of C- versus O-alkylation is discussed.

Aromatic substitution. XXXVII. Stannic and aluminum chloride catalyzed Friedel-Crafts alkylation of naphthalene with alkyl halides. Differentiation of kinetically and thermodynamically controlled product compositions, and the isomerization of alkylnaphthalenes

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAromatic substitution. XXXVII. Stannic and aluminum chloride catalyzed Friedel-Crafts alkylation of naphthalene with alkyl halides. Differentiation of kinetically and thermodynamically controlled product compositions, and the isomerization of alkylnaphthalenesGeorge A. Olah and Judith A. OlahCite this: J. Am. Chem. Soc. 1976, 98, 7, 1839–1842Publication Date (Print):March 1, 1976Publication History Published online1 May 2002Published inissue 1 March 1976https://doi.org/10.1021/ja00423a032RIGHTS & PERMISSIONSArticle Views867Altmetric-Citations55LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (432 KB) Get e-Alerts Get e-Alerts

Aromatic substitution. XXXVI. Aluminum trichloride and antimony pentafluoride catalyzed Friedel-Crafts alkylation of benzene and toluene with esters and haloesters

Aromatic substitution. XXXVI. Aluminum trichloride and antimony pentafluoride catalyzed Friedel-Crafts alkylation of benzene and toluene with esters and haloesters