- Nickel-Catalyzed Intramolecular Nucleophilic Addition of Aryl Halides to Aryl Ketones for the Synthesis of Benzofuran Derivatives
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A nickel-catalyzed intramolecular nucleophilic addition reaction of aryl halides to aryl ketones for the formation of benzofuran derivatives has been developed. A number of substrates bearing electron-donating or electron-withdrawing groups were subjected to the standard reaction conditions, giving the corresponding products in moderate to good yields.
- Zhu, Xiao-Rui,Deng, Chen-Liang
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p. 1842 - 1848
(2021/02/09)
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- Synthesis of benzofurans from the cyclodehydration of α-phenoxy ketones mediated by Eaton’s reagent
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Cyclodehydration of α-phenoxy ketones promoted by Eaton’s reagent (phosphorus pentoxide–methanesulfonic acid) is used to prepare 3-substituted or 2,3-disubstituted benzofurans with moderate to excellent yields under mild conditions. The method provides a facile access to benzofurans from readily available starting materials such as phenols and α-bromo ketones. The reaction is highly efficient, which is attributed to the good reactivity and fluidity of Eaton’s reagent. The reaction can be applied to prepare naphthofurans, furanocoumarins, benzothiophenes, and benzopyrans.
- Ma, Lin,Ma, Zhanwei,Zhang, Min,Zhou, Min
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p. 426 - 436
(2020/03/23)
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- Nickel catalyzed intramolecular oxidative coupling: synthesis of 3-aryl benzofurans
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Recent research has been focused on the transition metal-catalyzed reactions. Herein we have developed nickel-catalyzed synthesis of 3-aryl benzofurans fromortho-alkenyl phenolsviaintramolecular dehydrogenative coupling. Notably, simple O2gas served as an oxidant, without using any sacrificial hydrogen acceptor. The strategy enabled the synthesis of 3-aryl benzofurans in good to excellent yields.
- Aggarwal, Sakshi,Satyanarayana, Gedu,Sreenivasulu, Chinnabattigalla,Srinivas, Dasari
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p. 22264 - 22272
(2020/07/03)
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- Exogenous-oxidant-free electrochemical oxidative C-H sulfonylation of arenes/heteroarenes with hydrogen evolution
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An efficient and environmentally benign electrochemical oxidative radical C-H sulfonylation of arenes/heteroarenes was developed in this work. A series of significant diarylsulfones were prepared under mild catalyst- and exogenous-oxidant-free reaction conditions, which efficiently avoid the issues of desulfonylation or over-reduction of sulfonyl groups.
- Yuan, Yong,Yu, Yi,Qiao, Jin,Liu, Pan,Yu, Banying,Zhang, Wukun,Liu, Huilin,He, Min,Huang, Zhiliang,Lei, Aiwen
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supporting information
p. 11471 - 11474
(2018/10/20)
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- TfOH-SiO2 as an efficient and recyclable catalyst for synthesis of 3-arylbenzofurans
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A convenient process for the synthesis of 3-arylbenzofurans and their derivatives by 2-phenoxy-1-phenylethanones via TfOH-SiO2 catalyzed is developed. This method provides several advantages such as simple work-up procedure, simple post-treatme
- Wang, Baolong,Hu, Jiaxing,Zhang, Fanglin,Zheng, Hua
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p. 103 - 113
(2016/03/01)
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- Palladium(II)-catalyzed intramolecular addition of arylboronic acids to ketones
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A palladium(II)-catalyzed intramolecular addition of arylboronic acids to ketones was developed. Compared to Pd(OAc)2 catalysis system, cationic palladium complex with dppp as the ligand has higher catalytic activity and efficiency for wider sc
- Liu, Guixia,Lu, Xiyan
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p. 7324 - 7330
(2008/12/20)
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- Clay catalyzed facile cyclodehydration under microwave: Synthesis of 3-substituted benzofurans
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The preparation of 3-substituted benzofurans from α-phenoxy acetophenones and related compounds using clay under microwave irradiation is described. The inexpensive, reusable clay and non-solvent reaction conditions are the important features of the proce
- Meshram,Chandra Sekhar,Ganesh,Yadav
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p. 1273 - 1274
(2007/10/03)
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- Substituent Effect of 1,4-Benzenedicarbonitriles as Sensitizers on the Photoinduced Electron Transfer Reactions in Alcohol
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In the photosensitized electron transfer reaction of 6,6-diphenyl-1,4-dioxaspiro[4.5]decane in methanol (MeOH), the quantum yield is increased by the use of 2-methylbenzene-1,4-dicarbonitrile (2-methyl-BDC) or 2,5-dirnethylbenzene-1,4-dicarbonitrile (2,5-
- Suzuki, Masanori,Ikeno, Taketo,Osoda, Kazuhiko,Narasaka, Koichi,Suenobu, Tomoyoshi,Fukuzumi, Shunichi,Ishida, Akito
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p. 2269 - 2277
(2007/10/03)
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- Preparation of 1,4-Dicyanobenzene Derivatives and the Substituent Effect of the Sensitizers on Photoinduced Electron-Transfer Reactions
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Substituted 1,4-dicyanobenzenes are prepared as electron-accepting photosensitizers.The efficiency of some photosensitized reactions is influenced remarkably by the substituent(s) of 1,4-dicyanobenzene.By using mono or dimethylated dicyanobenzene, the rea
- Osoda, Kazuhiko,Pannecoucke, Xavier,Narasaka, Koichi
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p. 1119 - 1120
(2007/10/03)
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- 1,n-Radical ions. The photosensitized (electron transfer) formation of 1,5-radical cations
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The photosensitized (electron transfer) reactions of 3-phenyl-2,3-dihydrobenzofuran (8a), 5-methyl-3-phenyl-2,3-dihydrobenzofuran (8b), cis and trans-2-methoxy-1-phenylindane (9, cis and trans), 3,3-diphenyltetrahydrofuran (10), and 2,2-diphenyl-1-methoxycyclopentane (11) have been studied using 1,4-dicyanobenzene as an electron-accepting photosensitizer and acetonitrile-methanol (3:1) as solvent.These reaction conditions cause carbon-carbon bond cleavage of analogous acyclic β,β-diphenylethyl ethers to give products derived from the diphenylmethyl radical and the α-oxycarbocation intermediates.The purpose of this study was to determine if this reaction could be applied to five-membered cyclic derivatives to give 1,5-radical cations.The primary products from 8a and 8b were the dehydrogenated, aromatized 3-phenylbenzofurans 14a and 14b.These products react further; continued irradiation gave the methanol adducts, cis and trans-2-methoxy-3-phenyl-2,3-dihydrobenzofuran (15a and 15b, cis and trans).The only observed reaction of the indanes (9, cis and trans) was cis-trans isomerization.Deuterium was incorporated at the bis-benzylic position of 8 and 9 when the irradiation was carried out in acetonitrile-methanol-O-d.These results are consistent with reversible deprotonation from the radical cations.There was no evidence for carbon-carbon bond cleavage with either 8 or 9.The relative rate, deprotonation faster than carbon-carbon bond cleavage, is explained in terms of the conformation of the bond that cleaves in relation to the singly occupied molecular orbital (SOMO) of the radical cation.Oxidation potential measurements support the conclusion that the SOMO of 8 and 9 is largely associated with the fused phenyl ring and is therefore orthogonal to the benzylic carbon-carbon bond.Irradiation of cis or trans-2-methoxy-3-phenyl-2,3-dihydrobenzofuran (15a, cis or trans), under these conditions, leads to cis-trans isomerisation.The mechanism in this case involves the reversible loss of methanol.There is evidence that the addition of methanol to 14 involves the sensitizer radical anion - 14 radical cation pair.In contrast with the fused bicyclic systems, the monocyclic tetrahydrofuran 10 and the methoxycyclopentane 11 both cleave under these conditions; the products are the expected acetals 22 and 29 formed from the intermediate 1,5-radical cations.In 10 and 11 the SOMO, which is largely associated with the diphenylmethyl moiety, can overlap with the adjacent carbon-carbon bond and cleavage occurs as in analogous acyclic systems.Both 10 and 11 are relatively stable to irradiation under conditions that are identical except with acetonitrile as solvent (without methanol).We found no evidence for cyclization of the intermediates (1,5-radical cation or 1,5-diradical) into the terminal phenyl ring.
- Arnold, Donald R.,Fahie, Brian J.,Lamont, Laurie J.,Wierzchowski, Jacek,Young, Kent M.
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p. 2734 - 2743
(2007/10/02)
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- Anti-microbial alkyl substituted-2-nitro-3-phenylbenzofurans
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Methyl-substituted-2-nitro-3-phenylbenzofurans are prepared from methyl-substituted-3-phenylbenzofurans and are found to be useful antimicrobial agents.
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- 2-Nitro-3-phenylbenzofuran alkanoic (or propenoic) acids
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Optionally substituted 2-nitro-3-phenylbenzofuranalkanoic and -alkenoic acids which are active as antimicrobial agents, processes for their preparation and intermediates therefor are described.
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