Cross‐Dehydrogenative C−O Coupling of Oximes with Acetonitrile, Ketones and Esters

Chen, Zhenyu; Liang, Hua‐Ju; Chen, Ri‐xing; Chen, Lei; Tang, Xiang‐Zheng; Yan, Ming; Zhang, Xue‐Jing

doi:10.1002/adsc.201900370

Cited by 26 publications

(25 citation statements)

References 59 publications

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“…These above methods necessitate expensive Ir/Ru organometallic complexes and transition‐metal catalyst, which bring about some limitations, such as toxicity and metal contamination. Very recently, ultraviolet (UV) light‐induced‐coupling of sulfinates and arylhalides was reported . The high‐energy UV light is incompatible with some functional groups and leads to side reactions.…”

Section: Methodsmentioning

confidence: 99%

Hantzsch Ester as a Visible‐Light Photoredox Catalyst for Transition‐Metal‐Free Coupling of Arylhalides and Arylsulfinates

Zhu

et al. 2020

Chemistry A European J

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Diethyl 2,6‐dimethyl‐1,4‐dihydropyridine‐3,5‐dicarboxylate (HEH) has been utilized as a visible‐light photoredox catalyst for the cross coupling of arylhalides and arylsulfinates without transition metal, sacrificial agent, and mediator. This method is compatible with various functional groups and provides diaryl sulfones in good to high yields. Mechanistic studies indicate that this reaction undergoes the stepwise light irradiation of HE−, single electron transfer (SET) in donor–acceptor complex (DAC) from *HE− to arylhalide, trapping of aryl radical with sulfinate, and SET oxidation of sulfone radical anion by HE. to sulfone by the DAC method.

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Section: Methodsmentioning

confidence: 99%

Hantzsch Ester as a Visible‐Light Photoredox Catalyst for Transition‐Metal‐Free Coupling of Arylhalides and Arylsulfinates

Zhu

et al. 2020

Chemistry A European J

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“…Recently, the oxidative C-O coupling of oximes with acetonitrile, esters 52, and ketones 53 was realized [95] (Scheme 21). The authors suggested a radical mechanism in which the iminoxyl radical is generated from the oxime anion under the action of perfluorobutyl iodide through the formation of an EDA complex (electron donor-acceptor complex, which is also called charge-transfer complex).…”

Section: Scheme 18mentioning

confidence: 99%

Oxime radicals: generation, properties and application in organic synthesis

Krylov¹,

Paveliev²,

Budnikov³

et al. 2020

Beilstein J. Org. Chem.

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N-Oxyl radicals (compounds with an N–O• fragment) represent one of the richest families of stable and persistent organic radicals with applications ranging from catalysis of selective oxidation processes and mechanistic studies to production of polymers, energy storage, magnetic materials design and spectroscopic studies of biological objects. Compared to other N-oxyl radicals, oxime radicals (or iminoxyl radicals) have been underestimated for a long time as useful intermediates for organic synthesis, despite the fact that their precursors, oximes, are extremely widespread and easily available organic compounds. Furthermore, oxime radicals are structurally exceptional. In these radicals, the N–O• fragment is connected to an organic moiety by a double bond, whereas all other classes of N-oxyl radicals contain an R2N–O• fragment with two single C–N bonds. Although oxime radicals have been known since 1964, their broad synthetic potential was not recognized until the last decade, when numerous selective reactions of oxidative cyclization, functionalization, and coupling mediated by iminoxyl radicals were discovered. This review is focused on the synthetic methods based on iminoxyl radicals developed in the last ten years and also contains some selected data on previous works regarding generation, structure, stability, and spectral properties of these N-oxyl radicals. The reactions of oxime radicals are classified into intermolecular (oxidation by oxime radicals, oxidative C–O coupling) and intramolecular. The majority of works are devoted to intramolecular reactions of oxime radicals. These reactions are classified into cyclizations involving C–H bond cleavage and cyclizations involving a double C=C bond cleavage.

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“…The choice of the base was crucial and the best results were obtained with Cs 2 CO 3 and K 2 CO 3 , whereas Na 2 CO 3 gave only low yields under otherwise identical conditions. The same catalytic system also works for the C–S coupling of aryl halides and sulfinate salts …”

Section: Photocatalyst‐free Carbon–heteroatom Coupling Reactionsmentioning

confidence: 99%

Photochemical Strategies for Carbon–Heteroatom Bond Formation

2019

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Photochemistry enables new synthetic means to form carbon–heteroatom bonds. Photocatalysts can catalyze carbon–heteroatom cross‐couplings by electron or energy transfer either alone or in combination with a second catalyst. Photocatalyst‐free methods are possible using photolabile substrates or by generating photoactive electron donor‐acceptor complexes. This review summarizes and discusses the strategies used in light‐mediated carbon–heteroatom bond formations based on the proposed mechanisms.

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Cross‐Dehydrogenative C−O Coupling of Oximes with Acetonitrile, Ketones and Esters

Cited by 26 publications

References 59 publications

Hantzsch Ester as a Visible‐Light Photoredox Catalyst for Transition‐Metal‐Free Coupling of Arylhalides and Arylsulfinates

Hantzsch Ester as a Visible‐Light Photoredox Catalyst for Transition‐Metal‐Free Coupling of Arylhalides and Arylsulfinates

Oxime radicals: generation, properties and application in organic synthesis

Photochemical Strategies for Carbon–Heteroatom Bond Formation

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