Catalytic Friedel-Crafts Acylation Reaction Research Articles

ChemInform Abstract: Hafnium Trifluoromethanesulfonate [Hf(OTf)4] as a Unique Lewis Acid in Organic Synthesis

AbstractReview: [62 refs.

Hafnium Trifluoromethanesulfonate [Hf(OTf)4] as a Unique Lewis Acid in Organic Synthesis

AbstractThis microreview summarizes examples of Hf(OTf)4‐mediated or ‐catalyzed organic reactions. Hafnium triflate possesses four strongly electron‐withdrawing OTf groups, together with an ionic radius of intermediate range (Al < Ti < Hf, Zr < Sc < Ln), and has an oxophilic hard character typical of group IV metals. This Lewis acid shows outstanding performance in catalytic Friedel–Crafts acylation reactions and Mannich‐type reactions of imines, hydrazones, and N,O‐acetals. Several natural products have also been synthesized by use of Hf(OTf)4‐mediated or ‐catalyzed reactions. Moreover, Hf(OTf)4 has a number of potent features in carbohydrate syntheses. Hf(OTf)4 possesses many unique characteristics that distinguish it from other Lewis acids. The unique characteristics of Hf(OTf)4 should make this compound a major candidate for selection as a Lewis acid in the future.

ChemInform Abstract: The Catalytic Friedel-Crafts Acylation Reaction Using a Catalyst Generated from GaCl3 and a Silver Salt.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform Abstract: The Catalytic Friedel-Crafts Acylation Reaction and the Catalytic Beckmann Rearrangement Promoted by a Gallium(III) or an Antimony(V) Cationic Species.

The catalytic Friedel-Crafts acylation reaction and the catalytic Beckmann rearrangement are successfully carried out by using the active cationic species dichlorogallium(III) perchlorate and tetrachloroantimonium(V) hexafluoroantimonate(V), respectively, which were generated in situ from appropriate silver, gallium(III) or antimony(V) salts

ChemInform Abstract: Unexpectedly High Activity of Zn(OTf)2×6H2O in Catalytic Friedel—Crafts Acylation Reaction.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Unexpectedly High Activity of Zn(OTf)2 · 6H2O in Catalytic Friedel–Crafts Acylation Reaction

Zn(OTf)2 · 6H2O was used to promote Friedel–Crafts acylation of aromatics. The work describes the high activity and efficiency of Zn(OTf)2 · 6H2O in acylation of aromatics, and the catalyst has surpassed most metal triflates in dispensing when dried at high temperature under vacuum before use.

Application of the Catalytic Friedel—Crafts Acylation Reaction and Regioselectivity Correlations.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Application of the Catalytic Friedel-Crafts Acylation Reaction and ­Regioselectivity Correlations

A correlation was found between electronic properties and regioselectivity in the Friedel-Crafts reaction of substituted phenylacetic and benzoic acids with anisole, utilising substoichiometric (down to 1 mol%) amounts of catalyst. Relative reactivities of selected catalysts for this reaction were also studied.

A Highly Active Ytterbium(III) Methide Complex for Truly Catalytic Friedel—Crafts Acylation Reactions.

AbstractFor Abstract see ChemInform Abstract in Full Text.

A Highly Active Ytterbium(III) Methide Complex for Truly Catalytic Friedel-Crafts Acylation Reactions

The Friedel-Crafts acylation of anisole with acetic anhydride using ytterbium(III) tri[tris(nonafluorobutanesulfonyl)methide] was studied with respect to catalyst loading. A strong inhibitory effect due to the product became apparent from doping experiments and from examination of the kinetic data. This understanding allowed catalyst loadings to be reduced to as little as 0.1 mol% for effective acylation under a suitable temperature and pressure regime.

The Catalytic Friedel-Crafts Acylation Reaction of Aromatic Compounds with Carboxylic Anhydrides Using Combined Catalyst System of Titanium(IV) Chloride Tris(trifluoromethanesulfonate) and Trifluoromethanesulfonic Acid

Abstract Various aromatic ketones are prepared in good to high yields with carboxylic anhydrides using combined catalyst system of TiCl(OTf)3 and TfOH.

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.

Catalytic Friedel-Crafts acylation reactions using hafnium triflate as a catalyst in lithium perchlorate-nitromethane

Catalytic Friedel-Crafts acylation reactions were performed by using hafnium trifluoromethanesulfonate (hafnium triflate, Hf(OTf) 4) as a catalyst. The catalytic activity of the Lewis acid catalyst was much improved in lithium perchlorate-nitromethane (LiClO 4-MeNO 2) and the yield was up to 250,000% based on the catalyst. Various substituted benzenes reacted with acid anhydrides in the presence of a catalytic amount of Hf(OTf) 4 to give the corresponding aromatic ketones in high yields.

The Catalytic Friedel–Crafts Acylation Reaction Starting from Aromatic Compounds and Free Carboxylic Acids (or Their Trimethylsilyl Esters) by Promotion of Silicon(IV) Cationic Species via Mixed Anhydrides

Abstract In the presence of active cationic species generated from silicon(IV) chloride and silver perchlorate, carboxylic acids or their trimethylsilyl esters react with p-trifluoromethylbenzoic anhydride to form corresponding mixed anhydrides in situ. Then the catalytic Friedel–Crafts acylation reaction between initially formed mixed anhydrides and coexisted aromatic compounds smoothly proceeds at room temperature to afford the corresponding aromatic ketones in high yields. The above two sequential reactions are effectively promoted by the active silicon(IV) catalyst under mild conditions.

An Efficient Catalytic Friedel-Crafts Acylation Reaction of Equimolar Amounts of Aromatic Compounds and Free Carboxylic Acids or Their Trimethylsilylesters via Mixed Anhydrides

Abstract In the presence of an active catalyst generated from SiCl4 and AgClO4, the Friedel-Crafts acylation reaction between equimolar amounts of aromatic compounds and mixed anhydrides, formed in situ from free carboxylic acids (or their trimethylsilylesters) and p-trifluoromethylbenzoic anhydride, smoothly proceeds at room temperature to afford the corresponding aromatic ketones in high yields.

The Catalytic Friedel-Crafts Acylation Reaction Using a Catalyst Generated from GaCl3 and a Silver Salt

Abstract In the presence of a catalyst generated from GaCl3 and a silver salt (AgClO4 or AgSbF6), the Friedel-Crafts acylation reaction of aromatic compounds such as anisole and veratrole with acid anhydrides smoothly proceeds to afford the corresponding aromatic ketones in high yields.

The Catalytic Friedel-Crafts Acylation Reaction and the Catalytic Beckmann Rearrangement Promoted by a Gallium(III) or an Antimony(V) Cationic Species

The catalytic Friedel-Crafts acylation reaction and the catalytic Beckmann rearrangement are successfully carried out by using the active cationic species dichlorogallium(III) perchlorate and tetrachloroantimonium(V) hexafluoroantimonate(V), respectively, which were generated in situ from appropriate silver, gallium(III) or antimony(V) salts.