Friedel-Crafts chemistry.  11.  Boron, aluminum, and gallium tris(trifluoromethanesulfonate) (triflate):  effective new Friedel-Crafts catalysts

Oláh, George A.; Farooq, Omar; Farnia, S. Morteza F.; Oláh, Judith A.

doi:10.1021/ja00216a032

Cited by 166 publications

(85 citation statements)

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“…Owing to the large size of the ions, the initial survey calculations were performed by using the PM3 [30,31] semi-empirical algorithm, which was obtained as part of the Spartan '02 for Linux package (Wavefunction, Inc.). The starting points of the investigation were the protonated ions of compounds 1, 5 and 9 [3], to which we limited the calculations.…”

Section: Theoretical Calculationsmentioning

confidence: 99%

“…Cyclodehydrations of aromatic mono carboxylic acids, induced by polyphosphoric acid as a dehydrating agent have been routinely used to synthesize cyclic ketones [2,3]. These reactions are viewed to be intramolecular Friedel-Crafts acylations that occur by electrophilic mechanisms, for which a variety of acids have been used for effecting the cyclizations [4].…”

Section: Introductionmentioning

confidence: 99%

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Protonated nitro group as a gas-phase electrophile: Experimental and theoretical study of the cyclization of o-nitrodiphenyl ethers, amines, and sulfides

Moolayil

George

Srinivas

et al. 2007

J. Am. Soc. Mass Spectrom.

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A novel gas-phase electrophilic cyclization, initiated by the protonation of a nitro group, occurs for 2-nitrophenyl phenyl ether and for the analogous sulfide and amine, leading to heterocyclic intermediates in each case. Subsequently, the cyclic intermediates dissociate via two pathways: (1) unusual step-wise eliminations of two OH radicals to afford heterocyclic cations, [phenoxazine − H] + , [phenothiazine − H] + and [phenazine + H] + , and (2) expulsion of H 2 O, to yield a heterocyclic ketone, followed by loss of CO. The proposed structures of the gas-phase product ions and reaction mechanisms are supported by chemical substitution, deuterium labeling, accurate mass measurements at high mass resolving power, product-ion mass spectra obtained by tandem mass spectrometry, mass spectra of reference compounds, and molecular orbital calculations. Using a mass spectrometer as a reaction vessel, we demonstrate that, upon protonation, a nitro group becomes an electrophile and participates in cyclization reactions in the gas-phase.

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Section: Theoretical Calculationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Protonated nitro group as a gas-phase electrophile: Experimental and theoretical study of the cyclization of o-nitrodiphenyl ethers, amines, and sulfides

Moolayil

George

Srinivas

et al. 2007

J. Am. Soc. Mass Spectrom.

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“…We have found that gallium (III) trifluoromethanesulfonate [Ga(OTf) 3 , gallium triflate], acts as an effective but mild and nonhydrolysable Lewis acid catalyst for many organic synthetic transformations such as Friedel-Crafts alkylations, dehydration of oximes to the corresponding nitriles, Beckman rearrangement, etc. (33)(34)(35)(36). This catalyst can be easily recovered from the reaction mixture and reused, showing its significant potential as a safe and environmentally benign catalyst.…”

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confidence: 99%

Gallium (III) triflate catalyzed efficient Strecker reaction of ketones and their fluorinated analogs

Prakash

Mathew

Panja

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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The synthesis of ␣-aminonitriles and their fluorinated analogs has been carried out in high yield and purity by the Strecker reaction from the corresponding ketones and amines with trimethylsilyl cyanide using gallium triflate in dichloromethane. Monofluoro-, difluro-, or trifluoromethyl groups can be incorporated into the ␣-aminonitrile product by varying the nature of the fluorinated ketones. Study with various fluorinated and nonfluorinated ketones reveals that the choice of proper catalyst and the solvent system (suitable metal triflates as a catalyst and dichloromethane as a solvent) plays the key role in the direct Strecker reactions of ketones.three-component reaction ͉ ␣-aminonitriles

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“…The synthesis of aluminum trifluoromethanesulfonate from aluminum trichloride and triflic acid was published by Olah et al 1,2 in 1988. Aluminum triflate is a white solid with a high melting point 2 and acts as a strong, stable, oxophilic [3][4][5] Lewis acid that can easily be recycled and reused 6 due to its water-tolerant properties.…”

Section: Introductionmentioning

confidence: 99%

“…7 During initial investigations, aluminum trifluoromethanesulfonate was mainly used for Michael and Friedel-Crafts reactions, and it also functioned as a Lewis acid catalyst for the protection of alcohols, phenols, and thiophenols 8 with a variety of different protecting groups (i.e., methyl, ethyl, isopropyl, tert-butyl, acetyl, tetrahydropyranyl and tetrahydrofuranyl). 1,9,10 Recently, the utilization of aluminum trifluoromethanesulfonate has been studied in much more diversity, for example as a co-catalyst in metal-catalyzed reactions, 4,11 in the nucleophilic opening of epoxides, 5,12,13 cyclization, 14 substitution, 15 and other reactions.…”

Section: Introductionmentioning

confidence: 99%

Aluminum Trifluoromethanesulfonate

Plessis

2013

Synlett

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Friedel-Crafts chemistry. 11. Boron, aluminum, and gallium tris(trifluoromethanesulfonate) (triflate): effective new Friedel-Crafts catalysts

Cited by 166 publications

References 0 publications

Protonated nitro group as a gas-phase electrophile: Experimental and theoretical study of the cyclization of o-nitrodiphenyl ethers, amines, and sulfides

Protonated nitro group as a gas-phase electrophile: Experimental and theoretical study of the cyclization of o-nitrodiphenyl ethers, amines, and sulfides

Gallium (III) triflate catalyzed efficient Strecker reaction of ketones and their fluorinated analogs

Aluminum Trifluoromethanesulfonate

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