Effets de cryptands et activation de bases—VII

Handel, Henri; Pasquini, Miriam; Pierre, Jean‐Louis

doi:10.1016/0040-4020(80)80166-9

Cited by 17 publications

(21 citation statements)

References 5 publications

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“…Pierre et al. had proposed a cS N Ar mechanism for dehalogenation of haloarenes in 1980, as mentioned earlier . They had verified that the hydrogen atom delivered to the aryl halide had come from KH.…”

Section: Hydrides As Nucleophilesmentioning

confidence: 99%

“…Avery early example was the work of Pierre et al [27] who, in just as ingle paper that was published in 1980, studied the reaction of KH with aryl halides.T his report simply involved hydrodehalogenation of substrates 19 in tetrahydrofuran (THF) as solvent (Scheme 5). Thereactions were not pursued with detailed mechanistic investigations,but the observations made were illuminating.…”

Section: Concerted Nucleophilic Aromatic Substitution (Csnar)-early Dmentioning

confidence: 99%

“…[63] Pierre et al had proposed ac S N Ar mechanism for dehalogenation of haloarenes in 1980, as mentioned earlier. [27] They had verified that the hydrogen atom delivered to the aryl halide had come from KH. They had ruled out abenzyne intermediate in their reactions,a nd presented their proposal based on the observed order of reactivity (ArI > ArBr > ArCl) which was in contrast to the normal order of reactivity in astandard S N Ar reaction on iodobenzene 174 (Scheme 26).…”

Section: Hydrides As Nucleophilesmentioning

confidence: 99%

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Concerted Nucleophilic Aromatic Substitution Reactions

et al. 2019

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Recent developments in experimental and computational chemistry have identified a rapidly growing class of nucleophilic aromatic substitutions that proceed by concerted (cSNAr) rather than classical, two‐step, SNAr mechanisms. Whereas traditional SNAr reactions require substantial activation of the aromatic ring by electron‐withdrawing substituents, such activating groups are not mandatory in the concerted pathways.

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Section: Hydrides As Nucleophilesmentioning

confidence: 99%

Section: Concerted Nucleophilic Aromatic Substitution (Csnar)-early Dmentioning

confidence: 99%

Section: Hydrides As Nucleophilesmentioning

confidence: 99%

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Concerted Nucleophilic Aromatic Substitution Reactions

et al. 2019

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“…Pierre et al. hatte, wie oben erwähnt, bereits 1980 einen cS N Ar‐Mechanismus für diese Art der Dehalogenierung von Halogenaromaten vorgeschlagen . Damals wurde nachgewiesen, dass das an den Halogenaromaten abgegebene Wasserstoffatom vom KH stammte.…”

Section: Hydride Als Nukleophileunclassified

Konzertierte nukleophile aromatische Substitutionen

Rohrbach¹,

Sutherland-Smith²,

Pang

et al. 2019

Angewandte Chemie

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Jüngste Entwicklungen in der experimentellen und theoretischen Chemie haben zur Identifizierung einer schnell wachsenden Klasse von nukleophilen aromatischen Substitutionsreaktionen geführt, die einem konzertierten Mechanismus (cSNAr) folgen, und nicht dem klassischen, zweistufigen SNAr‐Mechanismus. Während klassische SNAr‐Reaktionen auf die substantielle Aktivierung des aromatischen Ringes durch elektronenziehende Substituenten angewiesen sind, ist eine solche Aktivierung für den konzertierten Reaktionsverlauf nicht zwingend nötig.

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“…[7] In addition, the negative charge in the transition state can be dispersed not only on an aromatic ring but also on al eaving group,t hereby making the CS N Ar reaction less sensitive to the electronic nature of the substrate. In fact, several reports dealing with nucleophilic aromatic substitution reactions of electron-neutral and electron-rich substrates have now been documented, including iodination, [8] hydride reduction, [9,10] fluorination, [11][12][13][14][15] amination, [16] silylation, [17] thionylation, [18] and aryl migration [19,20] reactions.…”

mentioning

confidence: 99%

N‐Heterocyclic Carbene Catalyzed Concerted Nucleophilic Aromatic Substitution of Aryl Fluorides Bearing α,β‐Unsaturated Amides

2019

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Concerted nucleophilic aromatic substitution (CSNAr) has emerged as a powerful mechanistic manifold, in which nucleophilic aromatic substitution can proceed in one step without the need to form a Meisenheimer intermediate. However, all of the CSNAr reactions reported thus far require a stoichiometric strong base or activating reagent, and no catalytic variants have yet been reported. Herein, we report an N‐heterocyclic carbene (NHC)‐catalyzed intramolecular cyclization of acrylamides that contain a 2‐fluorophenyl group on the nitrogen through a CSNAr reaction. By using this catalytic method, it is possible to synthesize an array of quinolin‐2‐one derivatives, which are common structural motifs in pharmaceuticals and organic materials. DFT calculations unambiguously revealed that this reaction proceeds through the concerted nucleophilic aromatic substitution of aryl fluorides, in which a stereoelectronic σ (Cipso‐Cβ)→ σ*(Cipso‐F) interaction critically contributes to the stabilization of the transition state for the cyclization.

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Effets de cryptands et activation de bases—VII

Cited by 17 publications

References 5 publications

Concerted Nucleophilic Aromatic Substitution Reactions

Concerted Nucleophilic Aromatic Substitution Reactions

Konzertierte nukleophile aromatische Substitutionen

N‐Heterocyclic Carbene Catalyzed Concerted Nucleophilic Aromatic Substitution of Aryl Fluorides Bearing α,β‐Unsaturated Amides

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