Directing group assisted copper-mediated aroylation of phenols using 2-bromoacetophenones

Baruah, Swagata; Borthakur, Somadrita; Gogoi, Sanjib

doi:10.1039/c7cc05383e

Cited by 10 publications

(4 citation statements)

References 34 publications

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“…In all of the above-mentioned metal-catalyzed decarbonylative cyclization reactions,i nsertion of the p-system occurs after the extrusion of carbon monoxide by means of CÀC/CÀN/CÀO activation. Herein, in continuation of our studies on metalcatalyzed novel transformations, [6] we describe an unprecedented decarbonylative alkyne insertion reaction, in which insertion of the p-system occurs before the extrusion of carbon monoxide by means of C À H/C À Cactivation. Notably, this decarbonylative cycloaddition reaction of 3-hydroxy-2phenylchromones with alkynes provides adiscrete procedure for the synthesis of spiro-indenebenzofuranones.Spirobenzofuranones are important motifs that are widely distributed in bioactive compounds,p harmaceuticals,a nd natural products.…”

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Ruthenium(II)‐Catalyzed Synthesis of Spirobenzofuranones by a Decarbonylative Annulation Reaction

et al. 2017

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The first decarbonylative insertion of an alkyne through C-H/C-C activation of six-membered compounds is reported. The Ru-catalyzed reaction of 3-hydroxy-2-phenyl-chromones with alkynes works most efficiently in the presence of the ligand PPh to provide spiro-indenebenzofuranones. Unlike previously reported metal-catalyzed decarbonylative annulation reactions, in the present decarbonylative annulation reaction, the annulation occurs before extrusion of carbon monoxide.

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Ruthenium(II)‐Catalyzed Synthesis of Spirobenzofuranones by a Decarbonylative Annulation Reaction

et al. 2017

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“…The resulting intermediate C could undergo a keto–enol tautomerism to generate the intermediate D , which is more easily to be trapped by a radical species. At the same time, the (hetero)aryl ketone is oxidized to (hetero)aryl glyoxylic acid, followed by the generation of acyl radical through a decarboxylation under copper catalysis 39,40 . The selective electrophilic addition of the acyl radical to the rhodacycle D gives the radical species E , followed by the sequential oxidation and deprotonation process to form intermediate F .…”

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confidence: 99%

Acyl radical to rhodacycle addition and cyclization relay to access butterfly flavylium fluorophores

Yin

Zhang

et al. 2019

Nat Commun

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Transition metal-catalyzed C–H activation and radical reactions are two versatile strategies to construct diverse organic skeletons. Here we show the construction of a class of flavylium fluorophores via the merge of radical chemistry and C–H activation starting from (hetero)aryl ketones and alkynes. This protocol is not only applicable to aryl ketones but also to heteroaryl ketones such as thiophene, benzothiophene and benzofuran, thus leading to structural diversity. Mechanism studies, including control experiments, intermediate separation, radical trapping, EPR and ESI-HRMS experiments, demonstrate that the key step lies in the addition of the acyl radical generated by the copper-catalyzed C–C bond cleavage of aryl ketone to the rhodacycle formed via the C–H activation of aryl ketone. The flavylium fluorophores feature butterfly symmetrical configuration, nearly planar skeleton and delocalized positive charge, and exhibit intriguing photophysical properties, such as tunable absorption and emission wavelengths and high quantum yields.

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“…White solid, yield 95.5 mg (82%), R f 0.45 (8:2, hexanes/ethyl acetate); 1 H NMR (500 MHz, CDCl 3 ) δ 8.4 (s, 1H), 7.67 (d, J = 5.2 Hz, 1H), 7.37 (d, J = 4.8 Hz, 1H), 6.43 (s, 1H) …”

Section: Methodsmentioning

confidence: 99%

Micelle-Enabled Photoassisted Selective Oxyhalogenation of Alkynes in Water under Mild Conditions

et al. 2018

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Using micelles of FI-750-M, visible light, photocatalysts, and inexpensive halogenating reagents, such as N-bromosuccinimide and N-chlorosuccinimde, selective oxyhalogenations of alkynes were achieved in water under very mild conditions. No halogenation at the aromatic rings was detected, and control experiments revealed the radical pathway. The easily conducted protocol exhibited high reproducibility, was readily adjusted to gram scale, and allowed for recycling of reaction medium and catalyst.

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Directing group assisted copper-mediated aroylation of phenols using 2-bromoacetophenones

Cited by 10 publications

References 34 publications

Ruthenium(II)‐Catalyzed Synthesis of Spirobenzofuranones by a Decarbonylative Annulation Reaction

Ruthenium(II)‐Catalyzed Synthesis of Spirobenzofuranones by a Decarbonylative Annulation Reaction

Acyl radical to rhodacycle addition and cyclization relay to access butterfly flavylium fluorophores

Micelle-Enabled Photoassisted Selective Oxyhalogenation of Alkynes in Water under Mild Conditions

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