Regioselective preparation of functional aryl ethers and esters by stepwise nucleophilic aromatic substitution reaction

Parthiban, Anbanandam

doi:10.1016/j.jfluchem.2014.03.005

Cited by 12 publications

(8 citation statements)

References 66 publications

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“…Di-substitution products 1o ′ and 1p ′ were observed with 2,3,4,5,6-pentafluorobenzonitrile and 2,3,4,5,6-pentafluoronitrobenzene allowing >1 equiv of HF to be liberated for each fluoroarene, thereby increasing the yield of the HF transfer product 2a . Multiple S N Ar reactions are expected and are consistent with previous reports for these fluoroarenes. , The reaction could also be applied to both symmetric and asymmetric alkyl and aryl internal alkynes, allowing the formation of 2b-i as products of HF transfer. Hydrofluorination tolerates examples of both electron-donating and electron-withdrawing groups, including free alcohol.…”

Section: Results and Discussionsupporting

confidence: 88%

“…Multiple S N Ar reactions are expected and are consistent with previous reports for these fluoroarenes. 34 , 35 The reaction could also be applied to both symmetric and asymmetric alkyl and aryl internal alkynes, allowing the formation of 2b-i as products of HF transfer. Hydrofluorination tolerates examples of both electron-donating and electron-withdrawing groups, including free alcohol.…”

Section: Results and Discussionmentioning

confidence: 99%

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Au(I) Catalyzed HF Transfer: Tandem Alkyne Hydrofluorination and Perfluoroarene Functionalization

et al. 2022

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HF transfer reactions between organic substrates are potentially useful transformations. Such reactions require the development of catalytic systems that can promote both defluorination and fluorination steps in a single reaction sequence. Herein, we report a catalytic protocol in which an equivalent of HF is generated from a perfluoroarene | nucleophile pair and transferred directly to an alkyne. The reaction is catalyzed by [Au(IPr)N i Pr 2 ] (IPr = N , N ′-1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene). HF transfer generates two useful products in the form of functionalized fluoroarenes and fluoroalkenes. Mechanistic studies (rate laws, KIEs, density functional theory (DFT) calculations, competition experiments) are consistent with the Au(I) catalyst facilitating a catalytic network involving both concerted S N Ar and hydrofluorination steps. The nature of the nucleophile impacts the turnover-limiting step. The cS N Ar step is turnover-limiting for phenol-based nucleophiles, while protodeuaration likely becomes turnover-limiting for aniline-based nucleophiles. The approach removes the need for direct handling of HF reagents in hydrofluorination and offers possibilities to manipulate the fluorine content of organic molecules through catalysis.

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Section: Results and Discussionsupporting

confidence: 88%

Section: Results and Discussionmentioning

confidence: 99%

Au(I) Catalyzed HF Transfer: Tandem Alkyne Hydrofluorination and Perfluoroarene Functionalization

et al. 2022

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“…Multiple SNAr reactions are expected and are consistent with previous reports for these fluoroarenes. 34,35 The reaction could also be applied to both alkyl and aryl internal alkynes allowing the formation of 2b-d as products of HF transfer. In every case, the hydrofluorination was 100 % trans-selective.…”

Section: Resultsmentioning

confidence: 99%

Au(I) Catalyzed HF Transfer: Tandem Alkyne Hydrofluorination and Perfluoroarene Functionalisation

Mulryan

Rodwell

Phillips

et al. 2021

Preprint

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HF transfer reactions between organic substrates are an incredibly rare class of transformation. Such reactions require the development of new catalytic systems that can promote both defluorination and fluorination steps in a single reaction sequence. Herein, we report a novel catalytic protocol in which an equivalent of HF is generated from a perfluoroarene | nucleophile pair and transferred directly to an alkyne. The reaction is catalysed by [Au(IPr)NiPr2] (IPr = N,N’-1,3-Bis(2,6-diisopropylphenyl)imidazol-2-ylidene) and is 100 % atom efficient. HF transfer generates two useful products in the form of functionalised fluoroarenes and fluoroalkenes. Mechanistic studies (rate laws, KIEs, DFT calculations, competition experiments) are consistent with the Au(I) catalyst facilitating a catalytic network involving both concerted SNAr and hydrofluorination steps. The nature of the nucleophile impacts the turnover-limiting step. The cSNAr step is turnover-limiting for phenol-based nucleophiles while proteodeauration likely becomes turnover-limiting for aniline-based nucleophiles. The new approach removes the need for direct handling of HF reagents in hydrofluorination and offers new possibilities to manipulate the fluorine content of organic molecules through catalysis.

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“…In this study, we have targeted the preparation of a new series of per-uorinated open-chain organic polymers. The polymers were prepared via nucleophilic aromatic substitution reaction (NAS) between diphenols and aromatic uorinated linkers according to the reported literature [5,14]. The di-phenols are two examples of azomethane-based di-phenol DAB-A-OH and diazo-based di-phenol DAB-Z-OH.…”

Section: Synthesis Of Organic Linkersmentioning

confidence: 99%

“…Focusing on the recent POFs, the class of uorinated ether-based polymers was demonstrated through metal-catalyzed coupling reactions and nucleophilic aromatic substitution reactions (NAS) between diols and uorinated linkers (general NAS mechanism Scheme S1) [14][15][16]. Regarding the NAS, the synthetic methodology relies on successfully substituting the C-F bond with strong nucleophiles containing oxygen such as aromatic phenoxide or aliphatic alkoxides.…”

Section: Introductionmentioning

confidence: 99%

Per-Fluorinated Azo- and Azomethane-Based Organic Polymers Developed Via Nucleophilic Aromatic Substitution Mechanism: Synthesis, Thermal, Optical Properties, Porosity and Environmental Applications

Altarawneh

El‐Kaderi

Richard

et al. 2022

Preprint

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A new series of ether-linked, per-fluorinated organic polymers bearing azo- (-N = N-) and azomethane (-C = N-) organic linkers was reported. The synthetic methodology relied on applying the nucleophilic aromatic substitution reaction (NAS) to fluorinated linkers (e.g. decafluorobiphenyl and hexaflourobenzene) and diols of azo- and azomethane linkers. The successful formation of the new structures revealing ether-linkage substitution of selected fluorine sites was confirmed by 1H-, 13C-, 19F-NMR and FTIR. All polymers were thermally stable in the range of 350–500 °C due to the variation of fluorine and nitrogen contents. The extended conjugation of the polymers was confirmed by the changes in the UV-Vis spectra of the organic linkers and their corresponding polymers. A notable hypsochromic shift was observed in all cases, which was more pronounced with azo-based fluorinated chains due to the H-bonding on the nitrogen sites, chain conformations and planarity. The optical band gap (Eg) of the polymers was determined from the UV-Vis. The Eg values of azo-based fluorinated polymers were higher by 1eV compared to their corresponding linkers. The 19F-NMR analysis confirmed two types of NAS on both the ortho- and para- positions of the fluorinated linkers. These connections created the possibility of developing cross-linked frameworks beside the open-chain confirmation with tailored hydrophobic nature. The cross-linking formation was characterized by porosity measurements, including surface area (SA), pore size and pore volume. The highest measured values were recorded for the azo-based polymer (DAB-Z-1h), which reached 438 m2/g and a pore volume of 0.35 cm3/g. A surface area of 105 m2/g was the lowest for the open-chain azomethane-based polymer (DAB-A-1O) with a pore volume of 0.0872 cm3/g. The beneficial formation of porous structures with varied hydrophobic nature was investigated as adsorbents for separating water/benzene, water/phenol and the selective binding of methane/carbon dioxide gases from the air. The most hydrophobic polymers that contain the decafluorbiphenyl linker were suitable for benzene separation, and the superior methane uptake values were 6.14 and 3.46 mg/g, for DAB-Z-1O and DAB-A-1O, respectively. On the other hand, DAB-Z-1h, with the highest surface area (438 m2/g) and rich with nitrogen sites, has the highest CO2 uptake at 298 K (17.25 mg/g).

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Regioselective preparation of functional aryl ethers and esters by stepwise nucleophilic aromatic substitution reaction

Cited by 12 publications

References 66 publications

Au(I) Catalyzed HF Transfer: Tandem Alkyne Hydrofluorination and Perfluoroarene Functionalization

Au(I) Catalyzed HF Transfer: Tandem Alkyne Hydrofluorination and Perfluoroarene Functionalization

Au(I) Catalyzed HF Transfer: Tandem Alkyne Hydrofluorination and Perfluoroarene Functionalisation

Per-Fluorinated Azo- and Azomethane-Based Organic Polymers Developed Via Nucleophilic Aromatic Substitution Mechanism: Synthesis, Thermal, Optical Properties, Porosity and Environmental Applications

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