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Palladium-catalyzed heterocyclization-coupling sequences have been developed starting from buta-1,2,3-trienyl carbinols and electron-deficient alkenes. Polysubstituted furans are formed where the heterocyclic ring originates from the elements of the butatrienyl carbinol while the electron-deficient olefin is incorporated as a C-3 substituent. In most cases, the reaction proceeds via a Heck-type pathway leading to the efficient formation of 3-vinylfurans. However, couplings with methyl vinyl ketone display a divergent behavior to afford selectively either Heck- or hydroarylation-type products depending on reaction conditions. 相似文献
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A novel oxidation-ring-contraction reaction took place when 4-substituted Hantzsch 1,4-dihydropyridines were treated with Oxone. This reaction pattern provided a convenient method for the synthesis of polysubstituted furans. 相似文献
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Kirsch SF 《Organic & biomolecular chemistry》2006,4(11):2076-2080
Despite attracting tremendous interest for well over a century, the field of furan syntheses is continuously and rapidly developing. This brief overview highlights recent progress in the syntheses of polysubstituted furans primarily guided by substitution pattern. Accordingly, methods are categorized as providing access to either di-, tri- or tetrasubstituted furans. 相似文献
5.
《Tetrahedron》1987,43(11):2533-2542
New and improved routes to polysubstituted furans are described, together with a survey of their reactivity in cycloaddition reactions with oxyallyl carbocations, producing polysubstituted 8-oxabicyclo[3.2.1]oct-6-en-3-ones. 相似文献
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Saman Damavandi Reza Sandaroos Maral Pashirzad 《Research on Chemical Intermediates》2012,38(8):1969-1974
A new catalyst-free, one-pot synthesis of polysubstituted furans is reported. A series of [4-(4-aryl)-5-(cyclohexylamino)-2-(pyridin-2-yl)furan-3-yl](pyridin-2-yl)methanones was synthesized via multicomponent reaction of 1,3-di(pyridin-2-yl)propane-1,3-dione, aryl aldehydes, and cyclohexyl isocyanide. 相似文献
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[Chemical reaction: see text] Polysubstituted furans and highly functionalized 2H-pyrans were prepared in good yields by DABCO-catalyzed reactions of alpha-halo carbonyl compounds with dimethyl acetylenedicarboxylate (DMAD) at room temperature. 相似文献
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A series of polysubstituted furans and dihydrofurans have been prepared from readily available oxodienes and bromonitromethane in modest to excellent yields. This facile synthetic method is developed on the basis of proprietary properties of nitro group such as strong electron-withdrawing ability and cleavability. The conversion of nitro-substituted dihydrofurans to furans is presumably realized by elimination of HNO2 under the aid of DABCO. 相似文献
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Easily accessible propargyl vinyl ethers are found to be acyclic precursors to construct furan derivatives. According to the reactive behavior of the substrates and the regulation of reaction conditions, three synthetic routes to polysubstituted furans via palladium-catalyzed reactions of propargyl vinyl ethers in situ-prepared from alkynoates and 2-yn-1-ols are presented herein. These methods could have potential application in synthetic and pharmaceutical chemistry for its facilitation and accessible starting materials. 相似文献
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The base-mediated reactions of 1,3-dicarbonyl compounds with bromoallenes used as an allyl dication equivalent were explored. The corresponding dimethyl methylenecyclopropane-1,1-dicarboxylates and 2,3,4-trisubstituted furans were efficiently synthesized. [reaction: see text] 相似文献
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An efficient one-pot two-step synthesis of polysubstituted furans is described using readily available 4,5-epoxy-2-alkynyl esters as starting materials. In the first step, reduction of these with SmI2 affords buta-1,2,3-trienyl carbinol intermediates which, in the second step, participate in Pd(0)-catalyzed cyclization reactions with aryl halides and triflates by a mechanism probably involving oxidative addition, intramolecular oxypalladation and reductive elimination steps. In this manner, up to four carbon substituents are incorporated onto the furan ring, with the aryl group being introduced at the furan 3- or 4-positions. These features make the method particularly suitable for regioselective synthesis of tetrasubstituted furans. 相似文献
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随着社会的发展,人类对能源的需求越来越多,但是地球上化石资源的储藏量逐渐减少,不可再生资源正面临枯竭,对人类的生存提出了挑战,寻找开发新型能源已迫在眉睫.众所周知,绿色化学。代表了当今化学工业的发展方向;绿色化学希望化合物的来源是绿色的,即源于那些可再生资源;其生产工艺环境友好, 相似文献
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《Green Chemistry Letters and Reviews》2013,6(2):109-115
Abstract Polyethylene glycol (PEG)-mediated facile one-pot synthesis of polysubstituted-tetrahydropyrimidines have been developed under mild and green reaction conditions. The obtained products are interesting nitrogen heterocyclic molecules that contain α- and β-amino acid blocks. PEG can be reused with minimum loss of its activity. 相似文献
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Sharf V. Z. Belen'kii L. I. Gurovets A. S. Karmanova I. B. 《Chemistry of Heterocyclic Compounds》1982,18(2):134-138
The principles of the reductive dehalogenation of a number of mono- and dibromosubstituted functional derivatives of thiophene and furan in the presence of a palladium complex applied to silica gel modified with -aminopropyl groups were investigated. A one-step method for the preparation of mono- and dideutero-substituted carbonyl compounds of the furan and thiophene series was developed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 176–180, February, 1982. 相似文献
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A facile and atom-economic method for the synthesis of 3a,6a-dihydro-furo[2,3-b]furan derivatives and polysubstituted furans starting from furylcarbionls has been developed. This protocol involved a domino Claisen rearrangement/dearomatizing electrocyclic ring-closure/aromatizing electrocyclic ring-opening sequence. 相似文献
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Under different conditions, the reaction of propargyl alcohols and terminal alkynes leads to the selective formation of 1,4-diynes and polysubstituted furans/pyrroles. Water is the only byproduct in the selective synthesis of 1,4-diynes and pyrroles, and the strategy for the furan synthesis is of 100% atom economy. 相似文献
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A variety of 3-substituted furans, including the natural products perillene and dendrolasin, are obtained in good yield via reductive annulation of 1,1,1-trichloroethyl propargyl ethers using catalytic Cr(II) regenerated by Mn/TMSCl. [reaction: see text] 相似文献
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Hydromagnesiation of 3-trimethylsilyl-2-propyn-1-o1 (1) followed by reaction with aldehydes or ketones affords (E)-3-trimethylsilyl-2-alken-1,4-diols (2), which can be readily dehydrated to 3-trimethylsilyl-2,5-dihydrofurans (3) by treatment with BF3OEt2. The compounds (3) are converted to furans (5) by epoxidation and subsequent treatment with H2SO4. 相似文献
20.
A green and novel procedure is described for the preparation of a series of ionic liquid containing alkylimidazolium-based or N-alkylpyridinium-based cations and hexafluorophosphate-based or tetrafluoroborate-based anions in one-pot solvent-free conditions to give excellent yields with shortened time. 相似文献