- Synthesis of polysubstituted furans from aryl gem-dibromoethenes
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[Figure not available: see fulltext.] Synthesis of 2,3,5-trisubstituted furans can be performed at 120°C in DMF using aryl gem-dibromoethenes and ethyl acetoacetate as the starting substrates under the assistance of Ag2CO3–Cs2/
- Zhang, Wensheng,Xu, Wenjing
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p. 615 - 617
(2017/08/30)
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- Copper-Mediated [3 + 2] Oxidative Cyclization Reaction of N-Tosylhydrazones and β-Ketoesters: Synthesis of 2,3,5-Trisubstituted Furans
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The first attempt at utilizing N-tosylhydrazones as two-carbon synthons has been successfully achieved, which underwent a copper-mediated [3 + 2] oxidative cyclization reaction to afford 2,3,5-trisubstituted furans in moderate to good yields. The features of this method include inexpensive metal catalyst, readily available substrates, high regioselectivity, and convenient operation. The studies provide important approaches for further exploration of the powerful and diverse reaction abilities of N-tosylhydrazones.
- Huang, Yubing,Li, Xianwei,Yu, Yue,Zhu, Chuanle,Wu, Wanqing,Jiang, Huanfeng
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p. 5014 - 5020
(2016/07/06)
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- Copper-Catalyzed Coupling of 2-Siloxy-1-alkenes and Diazocarbonyl Compounds: Approach to Multisubstituted Furans, Pyrroles, and Thiophenes
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We report herein copper(II)-catalyzed cyclization reactions of silyl enol ethers derived from methyl ketones with α-diazo-β-ketoesters or α-diazoketones to afford 2-siloxy-2,3-dihydrofuran derivatives or 2,3,5-trisubstituted furans, respectively, under mild conditions. The former cyclization products serve as versatile 1,4-diketone surrogates, allowing facile preparation of 2,3,5-trisubstituted furans, pyrroles, and thiophenes.
- Tan, Wei Wen,Yoshikai, Naohiko
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p. 5566 - 5573
(2016/07/14)
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- Cobalt(II)-catalyzed electrophilic alkynylation of 1,3-dicarbonyl compounds to form polysubstituted furans via π-π Activation
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Polysubstituted furans were obtained with excellent yields via the electrophilic alkynylation of 1,3-dicarbonyl compoundsws with phenyl- or ester-substituted brominated alkynes. The reaction is catalyzed by the inexpensive and readily available catalyst, cobalt(II) chloride, and has a wide substrate scope. The C(sp)-C(sp3) coupling occurs under mild conditions with short reaction times and does not require an inert atmosphere or ligands. It is proposed that the reaction proceeds through a chelation complex of cobalt(II) with the deprotonated 1,3-dicarbonyl compound.
- Roslan, Irwan Iskandar,Sun, Jiulong,Chuah, Gaik-Khuan,Jaenicke, Stephan
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p. 719 - 726
(2015/03/18)
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- Tuning radical reactivity using iodine in oxidative C(sp3)-H/C(sp)-H cross-coupling: An easy way toward the synthesis of furans and indolizines
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Molecular iodine was found to be an effective redox catalyst for the oxidative cross-coupling of carbonyl compounds with terminal alkynes. In this work, we demonstrated that iodine could tune radical reactivity through reversible C-I bond formation for co
- Tang, Shan,Liu, Kun,Long, Yue,Qi, Xiaotian,Lan, Yu,Lei, Aiwen
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supporting information
p. 8769 - 8772
(2015/05/20)
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- Cu(I)-catalyzed reaction of diazo compounds with terminal alkynes: A direct synthesis of trisubstituted furans
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A method for the synthesis of tri-substituted furans has been developed based on Cu(I)-catalyzed reaction of terminal alkynes with β-keto α-diazoesters. This method for the synthesis of 2,3,5-trisubstituted furans is operationally simple and applicable to
- Hossain, Mohammad Lokman,Ye, Fei,Zhang, Yan,Wang, Jianbo
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p. 6957 - 6962
(2015/03/14)
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- Direct oxidative coupling of enamides and 1,3-dicarbonyl compounds: A facile and versatile approach to dihydrofurans, furans, pyrroles, and dicarbonyl enamides
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An efficient manganese(III)-mediated oxidative coupling reaction between α-aryl enamides and 1,3-dicarbonyl compounds has been developed. A series of dihydrofurans and dicarbonyl enamides were synthesized in moderate to good yields. Moreover, these dihydrofurans could be readily transformed into the corresponding furans and pyrroles via the Paal-Knorr reaction.
- Li, Pan,Zhao, Jingjing,Xia, Chungu,Li, Fuwei
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p. 5992 - 5995
(2015/01/08)
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- Regioselective synthesis of multisubstituted furans via metalloradical cyclization of alkynes with α-diazocarbonyls: Construction of functionalized α-oligofurans
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Co(III)-carbene radicals generated from activation of α- diazocarbonyls by Co(II)-porphyrin complexes have been shown to undergo a new type of tandem radical addition reaction with alkynes that affords five-membered furan structures. The Co(II) complex of
- Cui, Xin,Xu, Xue,Wojtas, Lukasz,Kim, Martin M.,Zhang, X. Peter
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supporting information
p. 19981 - 19984
(2013/02/23)
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- Silver-mediated oxidative C-H/C-H functionalization: A strategy to construct polysubstituted furans
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A novel silver-mediated highly selective oxidative C-H/C-H functionalization of 1,3-dicarbonyl compounds with terminal alkynes for the creation of polysubstituted furans and pyrroles in one step has been demonstrated. Promoted by the crucial silver specie
- He, Chuan,Guo, Sheng,Ke, Jie,Hao, Jing,Xu, Huan,Chen, Hongyi,Lei, Aiwen
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scheme or table
p. 5766 - 5769
(2012/05/07)
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- One-pot synthesis of furans using base- and acid-supported reagents Na 2CO3/Al2O3-PPA/SiO2'
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A convenient method for the one-pot synthesis of furans from -keto esters and -halo ketones was developed using an acid- and base-supported reagent system Na2CO3/Al2O3-PPA/SiO2'. The condensation reaction of triketones, which are formed from the reaction of -keto esters with -halo ketones in the presence of Na2CO 3/Al2O3, was promoted by PPA/SiO2 to give the corresponding furans in good yields. This method is simple and easy to perform in comparison with stepwise processes, and the yields are good.
- Aoyama, Tadashi,Nagaoka, Takashi,Takido, Toshio,Kodomari, Mitsuo
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scheme or table
p. 619 - 625
(2011/04/15)
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- HETEROCYCLIC COMPOUND
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The present invention provides a heterocyclic compound represented by the following formula (I), which has a glucagon antagonistic action and is useful for the prophylaxis or treatment of diabetes and the like, a compound represented by wherein ring A is an optionally substituted benzene ring and the like; Y is a nitrogen atom and the like; X is -O- and the like; R4 is a hydrogen atom and the like; R5 and R6 are each independently a hydrogen atom and the like; R1 is an optionally substituted hydrocarbon group and the like; R2 is a hydrogen atom and the like; and R3 is -(CH2)3-COOH and the like, or a salt thereof.
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Page/Page column 70; 113
(2010/08/07)
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- Ionic liquid as catalyst and reaction medium: A Simple and Efficient Procedure for Paal-Knorr furan synthesis
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The ionic liquid 1-butyl-3-methyl-imidazolium hydrogen sulfate, [bmim]HSO4, efficiently catalyzes Paal-Knorr furan synthesis without any organic solvent. A wide range of aliphatic and aromatic 1,4-diketones easily undergo condensations to form furan derivatives, providing a general and convenient procedure. The Paal-Knorr reaction of ester-substituted 1,4-diketones is first reported. The ionic liquid can be recovered and reused for subsequent runs without any appreciable loss of efficiency.
- Wang, Gangqiang,Guan, Zhi,Tang, Rongchang,He, Yanhong
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experimental part
p. 370 - 377
(2010/04/04)
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- Free radical cyclization of 1,3-dicarbonyl compounds mediated by manganese(III) acetate with alkynes and synthesis of tetrahydrobenzofurans, naphthalene, and trifluoroacetyl substituted aromatic compounds
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Furan derivatives were obtained from radical cyclizations of 1,3-dicarbonyl compounds mediated by Mn(OAc)3 with phenyl acetylene 2a (14-66% yields). Naphthalene derivates 4a and 4b were produced in the treatments with 2a. In addition to these,
- Alagoz, Oguzhan,Yilmaz, Mehmet,Pekel, A. Tarik
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p. 1005 - 1013
(2007/10/03)
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- 2,3,4- or 2,3,5-trisubstituted furans: Catalyst-controlled highly regioselective ring-opening cycloisomerization reaction of cyclopropenyl ketones
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2,3,4- or 2,3,5-trisubstituted furans were highly regioselectively formed from the cycloisomerization reaction of the same starting cyclopropenes 1 via the subtle choice of the transition metal halides. Under the catalysis of 5 mol % PdCl2(CHs
- Ma, Shengming,Zhang, Junliang
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p. 12386 - 12387
(2007/10/03)
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- Manganese(II)- and (III)-mediated Free-radical Cyclisation of Alkenes, β-Keto Esters and Molecular Oxygen
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The reactions of substituted ethenes with β-keto esters in the presence of a mixture of manganese(II) and manganese(III) acetates, and molecular oxygen yielded substituted 1,2-dioxan-3-ols 3 in 14-95percent yields.Cobalt(III) acetate, potassium permanganate, lead(IV) acetate, copper(II) acetate, chromium(VI) trioxide, thallium(III) acetate, ammonium cerium(IV) nitrate and iron(III) perchlorate were also used in place of manganese(III) acetate.Effects on the product yields of substituents in the alkenes and β-keto esters have been examined and reaction mechanisms are discussed.
- Yamada, Takashi,Iwahara, Yoko,Nishino, Hiroshi,Kurosawa, Kazu
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p. 609 - 616
(2007/10/02)
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- Oxovanadium-induced oxidative desilylation of allylic and benzylic silanes
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Cinnamyltrimethylsilane underwent desilylation via one-electron oxidation with VO(OEt)Cl2, which was applied to the cross-coupling with the less oxidizable allylic silanes to give the corresponding 1,5-hexadienes. Chlorination or aromatization
- Fujii, Takashi,Hirao, Toshikazu,Ohshiro, Yoshiki
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p. 5601 - 5604
(2007/10/02)
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- VO(OR)Cl2-induced cyclization of diketene via ring opening
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Diketene undergoes a VO(OR)Cl2-induced cyclization with styrenes via ring opening to give 3-alkoxycarbonyl-2-methyl-5-phenyl-4,5-dihydrofurans.Desilylative aromatization to the furans is observed in the reaction with α-trimethylsilylstyrene.
- Hirao, Toshikazu,Fujii, Takashi,Ohshiro, Yoshiki
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- DIRECT SYNTHESIS OF FURANS BY 3 + 2 CYCLOADDITIONS BETWEEN RHODIUM(II) ACETATE STABILIZED CARBENOIDS AND ACETYLENES
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When appropriate substituents are used, rhodium(II) acetate catalyzed decomposition of diazocarbonyls in the presence of acetylenes results in the formation of furans, derived from dipolar intermediates.
- Davies, Huw M. L.,Romines, Karen R.
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p. 3343 - 3348
(2007/10/02)
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