Aromatic Nucleophilic Substitution Reactions.

Bunnett, J. F.; Zahler, Roland E.

doi:10.1021/cr60153a002

Cited by 1,020 publications

(522 citation statements)

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“…The product was confirmed by using GC-MS and NMR. 1 coMpetInG FInancIal Interests The authors declare no competing financial interests.…”

Section: -Iodobenzonitrile (2b)mentioning

confidence: 99%

“…Aromatic (heteroaromatic) halides are valuable and fundamental building blocks that are used to construct new carbon-carbon and carbon-heteroatom bonds in organic synthesis and drug design [1][2][3] . Many important classical cross-coupling reactions such as the Heck reaction, the Suzuki reaction and the Buchwald-Hartwig reaction, among others, use aryl halides as starting materials (Fig.…”

Section: Introductionmentioning

confidence: 99%

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Photo-induced iodination of aryl halides under very mild conditions

Liu

et al. 2016

Nat Protoc

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Aryl iodides are important precursors in synthetic chemistry that form carbon–carbon and carbon–heteroatom bonds. Most methods use transition-metal catalysts, which need to be scrupulously removed before the compounds can be used in the pharmaceutical and electronics industries, where only parts-per-million levels of transition metals are allowed. The aromatic Finkelstein iodination reaction is a powerful method of preparing valuable aryl iodides from cheap but less reactive aryl bromides and chlorides. This protocol describes a transition metal–free method for a photo-induced aromatic Finkelstein iodination reaction that is performed at room temperature (20 °C). With common aromatic bromides and sodium iodide (NaI) as the starting materials, as well as a catalytic amount of I2 as an additive, the corresponding aromatic iodides can be synthesized in yields ranging from 56 to 93% under UV light irradiation in the absence of any metal catalysts. Various functional groups such as nitrile, ester and amino can be tolerated, which will facilitate the further functionalization of the aromatic iodides. The procedure normally requires 38–40 h to complete

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“…The product was confirmed by using GC-MS and NMR. 1 coMpetInG FInancIal Interests The authors declare no competing financial interests.…”

Section: -Iodobenzonitrile (2b)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Photo-induced iodination of aryl halides under very mild conditions

Liu

et al. 2016

Nat Protoc

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“…In a masterly review, Bunnett and Zahler collected these puzzling results, called cine substitutions , re-opened the mechanistic discussion again, and stimulated new research in this area of nucleophilic aromatic substitution reactions (for a review, see [43] This result suggested the analogous mechanistic pattern also for other nucleophilic substitutions at non-activated arylhalides, and the Roberts group could prove this assumption with the same experimental technique using labeled fluorobenzene phenyllithium in ether [45] as well as labelled chlorobenzene 4n NaOH at 3508 [46].…”

Section: Scheme 11 Scheme 12mentioning

confidence: 99%

Rolf Huisgen: Some Highlights of His Contributions to Organic Chemistry

Rüchardt¹,

Sauer

Sustmann

2005

Helvetica Chimica Acta

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“…[23] Formally, tetrahedral anionic σ -complexes are considered the anionic intermediates in the S N Ar mechanism of electron-poor aromatics. [24] Consequently, these complexes have been useful as tools for the description of the S N Ar mechanism and much of the literature to date deals with kinetics and equilibrium measurements of the related Meisenheimer complexes. [25] Structural characterisation methods include NMR, [26 -30] UV/visible spectrophotometry, [30] MS [31] and X-ray structure determination.…”

Section: Introductionmentioning

confidence: 99%

Chemical exchange in novel spirobicyclic zwitterionic Janovsky complexes using dynamic ¹H NMR spectroscopy

Culf

Čuperlović-Culf

Ouellette

2008

Magnetic Reson in Chemistry

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Highly coloured Janovsky complexes have been known for over 120 years, being used in many colourimetric analytical procedures. In this present study, two novel and stable nitrocyclohexadienyl spirobicyclic, zwitterionic Janovsky anionic hydantoin σ -complexes, rac-1,3-diisopropyl-6-nitro-2,4-dioxo-1,3-diazaspiro[4.5]deca-6,9-dien-8-ylideneazinate, ammonium internal salt (1) and 1,3-diisopropyl-2,4-dioxo-1,3-diazaspiro[4.5]deca-6,9-dien-8-ylideneazinate, ammonium internal salt (2) have been prepared and characterised by NMR, electrospray ionization mass spectrometry (ESI-MS) and UV/visible methods. For the p-mononitro-substituted complex (2), we discovered chemical exchange behaviour using 1D saturation transfer and 2D exchange spectroscopy (EXSY) 1 H NMR techniques. The coalescence temperature was determined to be 62• Cind 3 -acetonitrile. Analysis of these data provided a Gibbs free energy of activation, G ‡, of +67 kJ mole −1 , a rate constant, k, coalescence of 220 Hz and an equilibrium constant, K eqm , of 0.98 as estimates of the exchange process in this solvent. Of the two mechanisms proposed for this fluxional behaviour, ring opening to a substituted benzene or proton exchange, a further theoretical modelling study of 1D 1 H NMR spectra was able to confirm that simple proton exchange between the two nitrogen sites of the hydantoin ring provided an accurate simulation of the observed experimental evidence. Interestingly, the o,p-dinitro-substituted complex (1) did not show any chemical exchange behaviour up to 150• Cind 3 -acetonitrile (to 75• C) and d 6 -dimethyl sulfoxide (DMSO). Molecular modelling at the MM2 level suggests that steric collisions of an N-acyl isopropyl substituent of the hydantoin ring with the ortho-nitro group of the spirofused cyclohexadienyl ring prevents the proposed proton exchange mechanism occurring in this case.

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Aromatic Nucleophilic Substitution Reactions.

Cited by 1,020 publications

References 375 publications

Photo-induced iodination of aryl halides under very mild conditions

Photo-induced iodination of aryl halides under very mild conditions

Rolf Huisgen: Some Highlights of His Contributions to Organic Chemistry

Chemical exchange in novel spirobicyclic zwitterionic Janovsky complexes using dynamic ¹H NMR spectroscopy

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Aromatic Nucleophilic Substitution Reactions.

Cited by 1,020 publications

References 375 publications

Photo-induced iodination of aryl halides under very mild conditions

Photo-induced iodination of aryl halides under very mild conditions

Rolf Huisgen: Some Highlights of His Contributions to Organic Chemistry

Chemical exchange in novel spirobicyclic zwitterionic Janovsky complexes using dynamic 1H NMR spectroscopy

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Product

Resources

About

Chemical exchange in novel spirobicyclic zwitterionic Janovsky complexes using dynamic ¹H NMR spectroscopy