The question of Friedel-Crafts transformylations. Acid-catalyzed reactions of aromatic aldehydes with arenes

Roberts, Royston M.; El‐Khawaga, Ahmed M.; Sweeney, Kevin M.; El‐Zohry, Maher F.

doi:10.1021/jo00384a038

Cited by 44 publications

(12 citation statements)

References 2 publications

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“…The carbon monoxide produced by the decarbonylation was presumed to react with the aromatic hydrocarbons in some unspecified way to produce the triarylmethanes and anthracenes. To ascertain the mechanism, a number of aromatic aldehydes with a variety of arenes and Lewis and Brønsted acid catalysts were examined [18]. In many reactions, triarylmethanes were observed that did not contain the aromatic moiety corresponding to the original aldehydes.…”

Section: Introductionmentioning

confidence: 99%

Microwave-Assisted Nafion-H Catalyzed Friedel–Crafts Type Reaction of Aromatic Aldehydes with Arenes: Synthesis of Triarylmethanes

2010

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A new solid acid Nafion-H, a perfluorinated sulfonic acid resin, catalyzed microwave-assisted synthesis of triarylmethanes is described. Various benzaldehydes react readily with arenes to provide the corresponding triarylmethanes in good to excellent yields. The reactions were carried out under solvent free conditions under microwave irradiation in a pressure vessel. The solvent free microwave irradiation methods appears to be an environmentally friendly synthetic protocol providing products in significantly shorter reaction times over traditional heating methods carried out in a pressure tube.

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Section: Introductionmentioning

confidence: 99%

Microwave-Assisted Nafion-H Catalyzed Friedel–Crafts Type Reaction of Aromatic Aldehydes with Arenes: Synthesis of Triarylmethanes

2010

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“…(a) release of ring strain (b) assistance by chelation (c) cleavage of stable functional fragments . In an alternative approach, C sp3 ‐C sp2 bond cleavage, although in an unrestrained manner, was observed in triaryl methanes (TRAMs) in presence of a stoichiometric amount of AlCl 3 . A similar type of C−C bond cleavage from TRAMs was noted by Li et al.…”

Section: Introductionmentioning

confidence: 56%

Iron‐Catalyzed Tandem C‐N and C–C bond Cleavage in Diaryl Methanamines: Use of Electron‐Rich Arenes as Leaving Group to Generate Triaryl Methanes

2018

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A facile FeCl3 catalyzed tandem C−N and C−C bond cleavage in N‐protected diaryl methanamines has been studied where the C−C bond cleavage, interestingly, results in the release of electron‐rich and sterically bulky arenes such as 1,3,5‐trimethoxybenzene or 3,5‐dimethoxytoluene. The tandem bond cleavage reaction generates triaryl methanes in mild conditions under air atmosphere. We found success in isolating the intermediate, formed through the preliminary C−N bond cleavage, and then converted the isolated intermediate to the final triaryl methanes by affecting the subsequent C−C bond cleavage. Several nucleophiles such as indoles, furans, 4‐methoxythiophenol and 1,3‐dimethoxybenzene were found effective under Lewis acidic conditions to cause the unusual yet facile tandem bond cleavage reaction in the diaryl methanamines. Use of electron‐rich and sterically bulky arenes as leaving groups in the present work highlights an innovative concept, which may potentially open up parallel avenues in organic synthesis.

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“…Reaction of 1 with benzene in the presence of triflic acid is well documented [5,6,12,15]. It occurs under mild conditions, at room temperature [5] or at 50°C [6] to give 3 in 30-90% yield along with secondary products.…”

Section: Acid Mediated Reactivity Of Benzaldehyde Towards Benzene Chmentioning

confidence: 99%

Superacid and H-Zeolite Mediated Reactions of Benzaldehyde with Aromatic Compounds and Cyclohexane. The Role of Mono- and Dicationic Intermediates

Koltunov¹,

Walspurger

Sommer³

2004

Catalysis Letters

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Reactions of benzaldehyde (1) and related compounds-3-pyridinecarboxaldehyde (9) and acetophenone with benzene, chlorobenzene, o-dichlorobenzene and cyclohexane in the presence of superacids or H-form zeolite, HUSY were (re)investigated. In accordance with previous data, 1 condenses with benzene in triflic acid (CF 3 SO 3 H) as well as on HUSY to give triphenylmethane. At elevated temperature 1 also reacts with chlorobenzene but is inert towards o-dichlorobenzene. While 1 does not react with cyclohexane in CF 3 SO 3 H)SbF 5 , 9 undergoes readily selective ionic hydrogenation to give 3-pyridilcarbinol (14). In the presence of excess of AlCl 3 , however, as well as on HUSY, 1 reacts with cyclohexane to produce toluene. The mechanistic aspects of these reactions are discussed. Opposed to earlier, repeatedly cited suggestions that the reactivity of 1 involves, as in case of 9, superelectrophilic diprotonated species, we show that a monocationic intermediate is the best rationale for these results.

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The question of Friedel-Crafts transformylations. Acid-catalyzed reactions of aromatic aldehydes with arenes

Cited by 44 publications

References 2 publications

Microwave-Assisted Nafion-H Catalyzed Friedel–Crafts Type Reaction of Aromatic Aldehydes with Arenes: Synthesis of Triarylmethanes

Microwave-Assisted Nafion-H Catalyzed Friedel–Crafts Type Reaction of Aromatic Aldehydes with Arenes: Synthesis of Triarylmethanes

Iron‐Catalyzed Tandem C‐N and C–C bond Cleavage in Diaryl Methanamines: Use of Electron‐Rich Arenes as Leaving Group to Generate Triaryl Methanes

Superacid and H-Zeolite Mediated Reactions of Benzaldehyde with Aromatic Compounds and Cyclohexane. The Role of Mono- and Dicationic Intermediates

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