The regioselectivity in the fluorination of dibenzofuran, diphenylether and biphenyl with N-F type of reagents

Zupan, Marko; Iskra, Jernej; Stavber, Stojan

doi:10.1016/0040-4020(96)00661-8

Cited by 30 publications

(16 citation statements)

References 45 publications

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“…A similar outcome was observed when nitromethane was used as solvent, while no fluorination occurred when acetic acid or methanol was used. Attempts to drive the reaction that occurred in acetonitrile by including additives such as trifluoroacetic acid [11], nitrobenzene [12], KHCO 3 , or NaOTf [10e] were unsuccessful. The use of excess fluorinating reagent (2 eq.)…”

Section: Resultsmentioning

confidence: 99%

Nuclear fluorination of 3,5-diarylisoxazoles with Selectfluor®

Stephens

Blake

2004

Journal of Fluorine Chemistry

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Section: Resultsmentioning

confidence: 99%

Nuclear fluorination of 3,5-diarylisoxazoles with Selectfluor®

Stephens

Blake

2004

Journal of Fluorine Chemistry

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“…[6][7][8] It is relatively costeffective compared to alternatives such as N-fluorobenzenesulfonimide (NFSI) and fluoropyridinium salts, is stable for extended periodso ft ime, [9] and does not require storage at low temperatures or under ap rotective atmosphere.V arious synthetic studies have demonstrated the ability of 1 to fluorinate 1,3-dicarbonyl compounds, enol esters, and even electron-rich arenes. [10][11][12][13][14][15][16][17][18] Av ariety of acyclic and cyclic alkyl and aryl ketones can also undergo direct a-fluorination reactions using 1 and analogous species, when heated to reflux in acetonitrile or methanols olution. [19][20][21] Reagent 1 is one of the more reactive electrophilic fluorinating reagents, as judged from recentk inetic studies.…”

Section: Introductionmentioning

confidence: 99%

The Electrophilic Fluorination of Enol Esters Using SelectFluor: A Polar Two‐Electron Process

Wood

Etridge

Kennedy

et al. 2019

Chemistry A European J

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The reactiono fe nol esters with SelectFluor is facile andl eads to the corresponding a-fluoroketones under mild conditions and, as ar esult, this route is commonly employed for the synthesis of medicinally importantc ompoundss uch as fluorinated steroids. However,d espite the use of this methodology in synthesis, the mechanism of this reactiona nd the influence of structureo nr eactivity are unclear.Arigorous mechanistic study of the fluorination of these substrates is presented,i nformed primarily by detailed and robust kinetic experiments. The resultso ft his study implicateapolar two-electron process via an oxygen-stabilised carbenium species, rather than as ingle-electron process involvingr adical intermediates. The structure-reactivity relationships revealed here will assist synthetic chemists in deploying this type of methodology in the syntheses of a-fluoroketones.Scheme1.The fluorination of steroid structures via enol ester intermediates.[a] S.Scheme2.Literature studies that implicate two-electron or single-electron reaction mechanisms.Scheme14. Values of 1 for the three different Hammett studies conductedd uring thiswork.Scheme15. Proposed mechanisms for the hydrolysisof( a) 3 and (b) 8c after fluorination.

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“…The overall yield of the fluorination products obtained from anisole (XVII) and NFSI at 105°C (no solvent) was considerably higher than in the fluorination of phenol ( [32]; N-fluorobenzene-1,2-disulfonimide in CDCl 3 (1.5) [34]. These data suggest weak dependence of the regioselectivity on the nature of N-F reagent and polarity of the medium provided that specific effects are absent.…”

Section: Fluorination Of Aromatic Compounds With N-fluorobenzenesulfomentioning

confidence: 62%

Fluorination of aromatic compounds with N-fluorobenzenesulfonimide under solvent-free conditions

2009

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Reactions of N-fluorobenzenesulfonimide with methylbenzenes, phenols, and phenol ethers were studied under solvent-free conditions. The rate constant ratio for the reactions with mesitylene and durene indicates polar mechanism of the process. Solvent-free fluorination of aromatic compounds with N-fluorobenzenesulfonimide in some cases is more selective than reactions with other N-F reagents in a solvent.Fluorinated aromatic compounds are widely used as pesticides, medicinal agents, and various functional materials; therefore, development of ecologically friendly and selective fluorination procedures seems to be an important problem [1][2][3]. During the past two decades, N-F reagents [1-17] have been extensively used as source of fluorine in mild and selective fluorination of organic compounds. In particular, such reagent is N-fluorobenzenesulfonimide (NFSI) [2,4,[7][8][9][18][19][20][21][22][23][24]. It is nonhygroscopic, stable to storage, and convenient to handle with. N-Fluorobenzenesulfonimide is quite reactive, but at the same time it exhibits a moderate oxidative ability [2], which is important for fluorination of organic compounds with low oxidation potentials. N-Fluorobenzenesulfonimide is commonly used to effect fluorination of carbanions, enolates, and enol ethers in the synthesis of fluorinated intermediate products necessary for the manufacture of medicinal agents [7][8][9]. Direct fluorination of aromatic compounds with NFSI was performed less frequently than with other N-F reagents, e.g., 1-chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane salts .The goal of the present work was to study the selectivity in fluorination of aromatic compounds, namely methyl-substituted benzenes, phenols, and phenol ethers, with NFSI in the absence of a solvent. The selectivity problem in electrophilic fluorination under these conditions remains poorly studied (cf. [22]).We have found that the yield of monofluoro derivatives in the fluorination of polymethylbenzenes

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The regioselectivity in the fluorination of dibenzofuran, diphenylether and biphenyl with N-F type of reagents

Cited by 30 publications

References 45 publications

Nuclear fluorination of 3,5-diarylisoxazoles with Selectfluor®

Nuclear fluorination of 3,5-diarylisoxazoles with Selectfluor®

The Electrophilic Fluorination of Enol Esters Using SelectFluor: A Polar Two‐Electron Process

Fluorination of aromatic compounds with N-fluorobenzenesulfonimide under solvent-free conditions

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