- Nickel-Catalyzed Decarbonyloxidation of 3-Aryl Benzofuran-2(3H)-ones to 2-Hydroxybenzophenones
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We have developed a protocol to facilitate the nickel-catalyzed decarbonyloxidation of 3-aryl benzofuran-2(3H)-ones to 2-hydroxybenzophenones under mild conditions, which is an efficient approach for the decarbonyloxidation of lactones in organic synthesis. A diverse range of substrates can undergo C(O)-O/C(O)-C bond cleavage to generate the target products in good yields. These 2-hydroxybenzophenones can be converted into a variety of compounds via reactions such as esterification, cyclization, and reduction.
- Tong, Zhou,Tang, Zhi,Au, Chak-Tong,Qiu, Renhua
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p. 8533 - 8543
(2020/07/16)
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- A benzofuran compound and its efficient catalytic synthesis method
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The invention discloses a to trifluoromethanesulfonic acid nickel as catalyst, in order to mandelic acid and phenol as raw materials, and efficient synthesis of the benzofuran compound of the method, this method has the advantages of low cost, high yield,
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Paragraph 0019; 0020
(2019/04/04)
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- Recyclable nickel-catalyzed C-H/O-H dual functionalization of phenols with mandelic acids for the synthesis of 3-aryl benzofuran-2(3: H)-ones under solvent-free conditions
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Herein, we developed a protocol for the efficient synthesis of 3-aryl benzofuran-2(3H)-ones under solvent-free conditions from phenols and mandelic acids using Ni(OTf)2 as a catalyst. A diverse range of mandelic acids and phenols undergo C-H/O-
- Tang, Zhi,Tong, Zhou,Xu, Zhihui,Au, Chak-Tong,Qiu, Renhua,Yin, Shuang-Feng
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supporting information
p. 2015 - 2022
(2019/04/27)
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- Strategy for Catalytic Chemoselective Cross-Enolate Coupling Reaction via a Transient Homocoupling Dimer
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A new strategy, a transient homocoupling dimer strategy, for direct catalytic oxidative cross-enolate coupling reactions is developed. Cross-enolate coupling products bearing a (contiguous) tetrasubstituted carbon center were obtained chemoselectively without the need for stoichiometric amounts of strong bases/metal oxidants, and thus, the present catalysis provides a general method for the synthesis of unnatural α,α-disubstituted amino acid motifs. The distinct transformation of azlactone and 2-acylimidazole units highlighted the synthetic utility of the present catalysis.
- Tanaka, Takafumi,Tanaka, Tsukushi,Tsuji, Taro,Yazaki, Ryo,Ohshima, Takashi
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supporting information
p. 3541 - 3544
(2018/06/26)
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- Direct enantioselective: C -acylation for the construction of a quaternary stereocenter catalyzed by a chiral bicyclic imidazole
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A direct enantioselective C-acylation of 3-substituted benzofuran-2(3H)-ones (with up to 97% ee) was developed using a chiral bicyclic imidazole catalyst OAc-DPI and an achiral tertiary amine additive DIPEA. The reaction mechanism for the direct C-acylation has been investigated using both experimental and theoretical studies.
- Wang, Mo,Zhang, Xiao,Ling, Zheng,Zhang, Zhenfeng,Zhang, Wanbin
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supporting information
p. 1381 - 1384
(2017/02/05)
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- Phosphine-Catalyzed Domino β/γ-Additions of Benzofuranones with Allenoates: A Method for Unsymmetrical 3,3-Disubstituted Benzofuranones
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A phosphine-catalyzed domino process of benzofuranones with allenoates has been developed which furnishes highly functionalized unsymmetrical 3,3-disubstituted benzofuranones in synthetically useful yields. The mechanism for the transformation is a tandem β-umpolung/γ-umpolung process.
- Huang, Zhusheng,Yang, Xiuqin,Yang, Fulai,Lu, Tao,Zhou, Qingfa
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supporting information
p. 3524 - 3527
(2017/07/17)
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- SbCl3-catalyzed solvent-free Friedel–Crafts reaction of phenols with mandelic acids to 3-aryl benzofuran-2(3H)-ones: Synthesis of spirocyclic 2,3-dihydrobenzofuran-2-ones
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A facile, SbCl3-catalyzed, one-pot, tandem Friedel–Crafts/lactonization reaction of phenols and mandelic acids has been developed under solvent-free conditions to afford 3-aryl benzofuran-2(3H)-ones in good to high yields (52–90%). Additionally
- Dhotare, Bhaskar B.,Choudhary, Manoj K.,Nayak, Sandip K.
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supporting information
p. 1772 - 1780
(2016/10/31)
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- (C6F5)3B Catalyzed Chemoselective and ortho-Selective Substitution of Phenols with α-Aryl α-Diazoesters
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The development of an efficient method for the site-selective substitution of unprotected phenols has long been considered as an attractive but challenging task. Herein, we describe a highly chemo- and ortho-selective substitution reaction of phenols with α-aryl α-diazoacetates with commercially available (C6F5)3B as the catalyst. This reaction proceeds under simple and mild conditions with high efficiency, it features a wide substrate scope and can be easily scaled up.
- Yu, Zhunzhun,Li, Yongfeng,Shi, Jiameng,Ma, Ben,Liu, Lu,Zhang, Junliang
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p. 14807 - 14811
(2016/11/23)
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- A Concise Synthesis of 2-(2-Hydroxyphenyl)acetonitriles via the o-Quinone Methides Generated from 2-(1-Tosylalkyl)phenols
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A concise synthesis of 2-(2-hydroxyphenyl)acetonitriles has been developed through reaction of trimethylsilyl cyanide and the o-quinone methides in situ generated from 2-(1-tosylalkyl)phenols under basic conditions. In addition, 2-(2-hydroxyphenyl)acetonitriles could be conveniently transformed to benzofuranones.
- Wu, Bo,Gao, Xiang,Chen, Mu-Wang,Zhou, Yong-Gui
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p. 981 - 984
(2016/02/18)
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- Chemistry of photogenerated α-phenyl-substituted o-, m-, and p-quinone methides from phenol derivatives in aqueous solution
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The enhanced photochemical reactivity of o-substituted phenols in its propensity to give o-quinone methide (o-QM) intermediates via excited state intramolecular proton transfer (ESIPT) was uncovered by Keith Yates as part of his now classic studies of photohydration of aromatic alkenes, alkynes, and related compounds. Photogeneration of QMs and the study of their chemistry along with potential biological applications are the focus of many groups. In this work, photochemical precursors to o-, m-, and p-QMs based on substituted phenols (hydroxybenzyl alcohols) and related compounds have been studied in aqueous solution as a function of pH and water content. The focus will be on QMs that are stabilized by an a-phenyl substituent, which enhances quantum yields for their formation, with the resulting QMs having longer lifetimes and easier to detect. Noteworthy is that all QM isomers can. be photogenerated with the o and m isomers being the most efficient, consistent with the Zimmerman "ortho-meta" effect. m-QMs have formal non-Kekule structures, and although they can be routinely photogenerated, are found to be most reactive. One m-QM was found, to undergo a photocondensation reaction at high pH giving rise to m-substituted oligomers. The mechanism, of QM formation in aqueous solution is believed to involve singlet excited phenols that undergo adiabatic deprotonation to give the corresponding photoexcited phenolate ion, which subsequently expels the hydroxide ion (photodehydroxylation). A pathway involving direct loss of water for the o-isomers is also possible in organic solvents.
- Diao, Li,Wan, Peter
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p. 105 - 118
(2008/09/18)
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- Some reactions of persistent benzofuranone radicals related to the 'old' diazonamide structure
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The benzofuranone dimers 9 and 10/11 readily (ca. 75°C) dissociate to the persistent radicals 16 and 17 respectively, which are stable to, dioxygen. The OMe analog 25 dissociates to form the radical 24, which reacts with dioxygen of TEMPO to give 26.
- Magnus, Philip,Venable, Jennifer D.,Shen, Lan,Lynch, Vince
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p. 707 - 710
(2007/10/03)
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- Anionic Homologous Fries Rearrangement of O-(2-Methylaryl)carbamates. A Regiospecific Route to Benzo[b]furan-2(3H)-ones including an Unnamed Metabolite from Helenium Species
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A new LDA mediated O → C carbamoyl migration, 3 provides a general and efficient route to aryl acetamides 5, precursors to the benzo- and naphthofuranones 7, one of which serves as a starting material for a short synthesis of naturally-occurring benzofuranolactol 11 isolated from several Helenium species.
- Kalinin,Miah,Chattopadhyay,Tsukazaki,Wicki,Nguen,Coelho,Kerr,Snieckus
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p. 839 - 841
(2007/10/03)
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- Compounds for the treatment of urinary incontinence
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The invention concerns compounds having the formula I STR1 wherein Ar is a phenyl or benzyl group which is optionally substituted with hydroxy or alkoxy;R 1 is hydrogen, lower alkyl, lower alkoxy, hydroxy;R 2 is hydrogen, lower alkyl;R 3 is NR 4 R 5, whereinR 4 and R 5 which can be the same or different, are lower alkyl, or wherein R 4 and R 5, when taken together, form a ring with the nitrogen atom, whereby said ring optionally is substituted with lower alkyl;n is 0 or 1;m is 2 or 3 andtheir salts with physiologically acceptable acids and when the compounds can be in form of optical isomers, the racemic mixture and the individual isomers, for the treatment of disorders of the urinary bladder.
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- Electron Transfer Reactions. Reaction of Furanones and Bifurandiones with Potassium and Oxygen
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Treatment of furanones (1a - c, 25, 34) and bifurandiones (23, 37) with potassium in THF gave rise to radical anion intermediates, which reacted with oxygen to give superoxide and ultimately products derived through the reaction of superoxide with the starting furanones and bifurandiones.Thus, the reaction of 1a with potassium gave a mixture of 4-oxo-2,2,4-triphenylbutanoic acid (7a), 1,3,3-triphenyl-2-propen-1-one (11a), and benzoic acid (12).The reaction of 11a itself, under similar conditions, gave a mixture of benzophenone (18a) and 12.Similar reactions have been observed in the case of 1b and c.The bifurandione 23, on treatment with potassium, gave a mixture of the 2(5H)-furanone 25, 2,3-diphenylpropenoic acid (31), and 12.The reaction of 25 itself with potassium under similar conditions gave the same mixture of 31 and 12.Treatment of 3-phenyl-2(3H)-benzofuranone (34) with potassium, however, did not give any isolable product; only the starting material could be recovered.Under similar conditions, the bifurandione 37 gave the fragmentation product 34.Cyclic voltammetric studies have been employed to measure the reduction potentials, leading to radical anions, and these intermediates have been characterized through their electronic spectra.
- Pandey, Bipin,Tikare, Ravindra K.,Muneer, Mohammed,Kamat, Prashant V.,George, Manapurathu V.
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p. 917 - 928
(2007/10/02)
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- ELECTRO-ORGANIC REACTIONS. PART 25. THE ROLE OF CHROMIUM(III) IN THE MODIFICATION OF CATHODIC PINACOLISATION
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The presence of chromium(III) chloride, both hydrated and anhydrous, profoundly alters the course of cathodic in dimethylformamide solutions of benzophenone, benzaldehyde, β-ionone, β-ionylidene acetaldehyde, and retinal.Pinacolisation is enhanced at the expense of formation of the corresponding alcohol.Furthermore the relevant reduction potential is lowered.The mechanism of the reaction has been investigated using voltammetric and coulometric experiments combined with a detailed analysis of preparative-scale reductions under a variety of conditions.The stereochemical course of the reactions has also been considered.In total the results provide compelling evidence in favour of the key reducible intermediate being a carbonyl compound-Cr(III) complex which is formed via the corresponding Cr(III) species with homogenous, inner sphere, re-oxidation playing a crucial role.This is contrary to earlier suggestions invoking the participation of electrogenerated Cr(II) as the reductant.
- Sopher, David W.,Utley, James H. P.
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p. 1361 - 1368
(2007/10/02)
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- Photochemical and Thermal Transformations of 2(3H)-Furanones and Bis(benzofuranones). A Laser Flash Photolysis study
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Transformations of the 2(3H)-furanones 1-4 and bis(benzofuranones) 16-18 under steady-state photolysis and thermolysis are reported.Irradiation of 1 in benzene gives a mixture of the decarbonylated product 5 (62percent) and the cyclized phenanthrene derivative 10 (15percent).Similar results were obtained when the photolysis of 1 was carried out in methanol and acetone.Irradiation of 2 in benzene and methanol gave exclusively the decarbonylation product 6, whereas, in acetone, a mixture of the rearranged lactone 13 and and its cyclized product, 15, was obtained.Irradiation of both 3 and 4 gave the cyclized products 11 and 12, respectively.In contrast, the photolysis of the bis(benzofuranone) 16 in cyclohexane gave 3-phenylbenzo-2-(3H)-furanone (25), whereas the photolysis in methanol led to a mixture of methyl α-(2-hydroxyphenyl)phenylacetate (34) and 3-hydroxy-3-phenylbenzo-2(3H)-furanone (31).Similar results were obtained in the irradiation of 17 and 18.Neat thermolysis of furanones 1-3 at 350-450 deg C gave the decarbonylated products 5, 6, and 37 in 36-80 percent yields, whereas furanone 4 underwent facile isomerization to 5-benzyl-3,4,5-triphenyl-2(5H)-furanone (38), upon refluxing in diphenyl ether (ca. 255 deg C).Heating of bis(benzofuranones) 16-18 in refluxing cumene (ca. 150 deg C) gave the corresponding furanones 25-27 in 62-68 percent yields.Laser flash photolysis of furanones 1-4 at 248 and 337 nm leads to absorption spectral changes that can be explained in terms of singlet-mediated decarbonylation (φ = 0.3 for 2 in methanol, λex = 248 nm) and cyclization, i.e., dihydrophenanthrene formation (φ = 0.1-0.5 for 1, 3, and 4 in benzene and methanol, λex = 337 nm).The triplets of the furanones generated under energy-transfer sensitization by benzophenone in benzene are relatively long lived (r = 1.2-12 μs) and exhibit absorption maxima at 330-370 nm (εmax = (11-14) * 103 M-1 cm-1); these spectral and kinetic features appear to be characteristic of the styrene and cis-stilbene chromophores, constrained into planar configurations.Upon laser flash photolysis at 248 nm in methanol, bis(benzofuranones) 16-18 undergo facile fragmentation to the corresponding radicals 19-21, characterized by sharp and intense absorption maxima at ca. 330 nm, in addition to broad and weak absorption band systems at 500-600 nm; these radical species are the primary intermediates implicated in the formation of various final products in the course of steady-state photolysis of 16-18 under different conditions.
- Lohray, B. B.,Kumar, C. V.,Das, P. K.,George, M. V.
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p. 7352 - 7359
(2007/10/02)
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- Furano Compounds: Part IL - Solvolytic Rearrangement of Ketoximes in Benzofuran Series and PMR Study of Benzofuryl-2-alkyl(aryl) Ketoximes
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Solvolytic rearrangement of tosylates of 3-alkyl(aryl)-benzofuryl-2-alkyl ketoximes and 2-substituted(and unsubstituted)benzofuryl-3-methyl ketoximes with aqueous methanol depends upon their configurations.The tosylates of 2-ethyl(benzyl)benzofuryl-3-methyl ketoximes obtained in alkaline medium do not undergo solvolytic rearrangement under similar conditions.The isomerisation of anti-isomers of the above mentioned ketoximes to syn-forms with hydrogen chloride is unsuccesful.The configurations of syn- and anti-isomers of benzofuryl-2-alkyl(aryl) ketoximes have been studied by PMR spectroscopy.
- Chatterjea, J. N.,Singh, K. R. R. P.
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p. 1053 - 1056
(2007/10/02)
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