Metal‐Free Oxidative Annulation/Cyclization of 1,6‐Enynes for the Synthesis of 4‐Carbonylquinolines

He, Wei; Wang, Dawei

doi:10.1002/adsc.201900013

Cited by 15 publications

(16 citation statements)

References 60 publications

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“…On the basis of the above results and previous reports, a tentative mechanism is depicted in Scheme . The first step of this transformation is the formation of the tert ‐butoxy radical and NO radical generated by homolysis of TBN .…”

Section: Resultssupporting

confidence: 65%

“…We initially commenced our investigation with our previous reported reaction conditions using ethyl 3‐phenyl‐3‐((3‐phenylprop‐2‐yn‐1‐yl)‐amino)‐acrylate 1 a and TBN as the model substrates. Gratifyingly, a 50% yield of 6‐benzoyl‐2‐(ethoxycarbonyl)‐3‐phenyl‐pyrazine 1‐oxide 2 a was obtained at room temperature using trifluoroethanol as the solvent (Table , entry 1).…”

Section: Resultsmentioning

confidence: 99%

“…However, the direct construction of six membered N‐containing compounds from 1,5‐enynes by [5+1] radical cycloaddition reaction is still a challenging task due to the manifold cyclization modes . Very recently, our group reported a metal‐free oxidative annulation reaction of 1,6‐enynes for the synthesis of 4‐carbonylquinolines using TBN as the oxidant . In this context, we hypothesized that if 1,5‐enynes were introduced into this oxidative systems, an intramolecular radical cyclization/NO group insertion sequence could be realized (Scheme ‐c, path a).…”

Section: Introductionmentioning

confidence: 99%

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Metal‐Free Oxidative [5+1] Cyclization of 1,5‐Enynes for the Synthesis of Pyrazine 1‐Oxide

Zhao

Zou

et al. 2020

Adv Synth Catal

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A chemo‐selective nitrosylation of 1,5‐enynes via a sequence of NO radical incorporation and intramolecular radical cyclization was reported. The formation of two C−N bonds and one C−O bond make this [5+1] cycloaddition reaction an efficient approach to synthesize pyrazine 1‐oxides in moderate to good yields. Metal‐free, short reaction time and mild conditions render this strategy more practical, eco‐friendly and convenient. Synthetic utility of this protocol is highlighted by scaffolds diversification.

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Section: Resultssupporting

confidence: 65%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Metal‐Free Oxidative [5+1] Cyclization of 1,5‐Enynes for the Synthesis of Pyrazine 1‐Oxide

Zhao

Zou

et al. 2020

Adv Synth Catal

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“…Xia group in 2019, reported a method for the synthesis of 4‐carbonylquinolines ( 10 ) via oxidative annulation of 1,6‐enynes ( 9 ) under a metal‐free condition. Dioxygen and TBN serve as green sustainable oxidant in this radical annulation (Scheme ) …”

Section: Outlines Of the Reactions Involving Tbnmentioning

confidence: 99%

“…Dioxygen and TBN serve as green sustainable oxidant in this radical annulation (Scheme 7). [17] The proposedm echanism is based on preliminarym echanistic studies that include radicalt rappinga nd isotope labeling experiments. Initially, tert-butoxy radical andN Or adicals are generated by thermal homolytic cleavage of TBN.…”

Section: Oxidationmentioning

confidence: 99%

tert‐Butyl Nitrite (TBN), a Multitasking Reagent in Organic Synthesis

Dahiya

Sahoo

Alam

et al. 2019

Chemistry An Asian Journal

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The upsurge interesti nt he development of efficient methodologies for the constructiono fn itrogen-containing frameworks via the use of expedient reagents have been creating ar enaissance in contemporary organic chemistry.I nt his perspective, tertbutyl nitrite (TBN) is an emerging building block. Due to its uniques tructuralf eatures, it shows differential reactivity under different reaction conditions. These diverse reactivities have resulted in the construction of ad iverse array of complex N-containing molecules. The primary objective of the presentr eview is to bring the latest findings of TBN in terms of its applications in reactions (oxidation, diazotization, nitrosation, nitration, oximation, N-synthon, and miscellaneous reactions) into the limelight.F or simplicity and brevity,r eactions in each section are explained with the mechanism of formation and selected examples are given.Scheme1.Differential reactivity of TBN. 4455 MinireviewScheme4.Visible-light-promoted synthesis of selenide ethers.Scheme5.Proposed mechanism for visible-light-promoted synthesis of selenide ethers.Scheme6.TBN-mediated synthesis of selenide ethers.Scheme7.Metal-free synthesis of 4-carbonylquinolines.Scheme8.Proposed mechanism for synthesis of 4-carbonylquinolines.Scheme9.TBN-mediated demethylative borylation of methylarenes.Scheme10. Plausible mechanism for demethylative borylation of methylarenes.Scheme11. Trifluoromethylation of various aromatic amine substrates.Scheme12. Copper-catalyzed isoperfluoropropylation of anilines.Scheme13. Plausible mechanism for Cu-catalyzed isoperfluoropropylation of anilines.Scheme14. TBN-mediateddiazotizative allylation of aromatic amines.Scheme15. Oxidativecyanomethylationo fa lkenes via CÀHb ond activation.Scheme16. TBN-mediatedand Cu-catalyzedsynthesis of thioether.

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Cascade Reaction of α, β‐Unsaturated Ketones and 2‐Aminoaryl Alcohols for the Synthesis of 3‐Acylquinolines by a Copper Nanocatalyst

et al. 2021

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3‐Acylquinolines possess widespread applications in functional chemicals. However, the convenient and selective synthesis of such important substructures has to date remained a challenge. Herein, we report a method to access 3‐acylquinolines from α, β‐unsaturated ketones and 2‐aminoaryl alcohols in one pot with a copper nanocatalyst supported on nitrogen‐silica‐doped carbon (Cu/N−SiO2−C). Mechanistically, the construction of the product involves a cascade procedure including radical‐type oxidation of 2‐aminoaryl alcohols, aza‐Michael addition and annulation. This developed protocol proceeds with merits of mild reaction conditions, good functional group tolerance, earth‐abundant and reusable copper catalyst, easily available stocks and O2 as the sole oxidant, which provides an alternative way for the sustainable synthesis of quinoline derivatives.

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Metal‐Free Oxidative Annulation/Cyclization of 1,6‐Enynes for the Synthesis of 4‐Carbonylquinolines

Cited by 15 publications

References 60 publications

Metal‐Free Oxidative [5+1] Cyclization of 1,5‐Enynes for the Synthesis of Pyrazine 1‐Oxide

Metal‐Free Oxidative [5+1] Cyclization of 1,5‐Enynes for the Synthesis of Pyrazine 1‐Oxide

tert‐Butyl Nitrite (TBN), a Multitasking Reagent in Organic Synthesis

Cascade Reaction of α, β‐Unsaturated Ketones and 2‐Aminoaryl Alcohols for the Synthesis of 3‐Acylquinolines by a Copper Nanocatalyst

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