- Iodine-Catalyzed Synthesis of Substituted Furans and Pyrans: Reaction Scope and Mechanistic Insights
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Substituted pyrans and furans are core structures found in a wide variety of natural products and biologically active compounds. Herein, we report a practical and mild catalytic method for the synthesis of substituted pyrans and furans using molecular iodine, a simple and inexpensive catalyst. The method described is performed under solvent-free conditions at an ambient temperature and atmosphere, thus offering a facile and practical alternative to currently available reaction protocols. A combination of experimental studies and density functional theory calculations revealed interesting mechanistic insights into this seemingly simple reaction.
- Pace, Domenic P.,Robidas, Rapha?l,Tran, Uyen P. N.,Legault, Claude Y.,Nguyen, Thanh Vinh
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p. 8154 - 8171
(2021/06/28)
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- Acid-Promoted One-Pot Synthesis of Substituted Furan and 6-Methylpyrazin-2(1 H)-one Derivatives via Allene Intermediate Formed in Situ
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Under the acidic conditions, substituted furans were constructed from γ-alkynyl ketones through corresponding allene intermediates in one-pot. The methodology was also tailored to a series of the Ugi reaction products for the synthesis of 6-methylpyrazin-2(1H)-one derivatives. The current method offered significant advantages for the combinatorial applications of these chemical scaffolds.
- Lei, Jie,Xu, Zhi-Gang,Tang, Dian-Yong,Li, Yong,Xu, Jia,Li, Hong-Yu,Zhu, Jin,Chen, Zhong-Zhu
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p. 292 - 297
(2018/05/24)
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- Auto-Tandem Catalysis-Induced Synthesis of Trisubstituted Furans through Domino Acid-Acid-Catalyzed Reaction of Aliphatic Aldehydes and 1,3-Dicarbonyl Compounds by using N-Bromosuccinimide as Oxidant
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A simple aluminium(III) chloride-catalyzed synthesis of tri-substituted furans from aliphatic aldehydes and 1,3-dicarbonyl compounds was developed by using N-bromosuccinimide (NBS) as an oxidant. This method was effective for the synthesis of various furan derivatives. Some of the products were not accessible with the previously reported methods. Mechanically, this reaction involved an auto-tandem catalysis based on a newly reported acid-acid-catalyzed tandem reaction to ensure that furans were successfully synthesized. (Figure presented.).
- Huang, Wenbo,Liu, Changhui,Gu, Yanlong
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supporting information
p. 1811 - 1818
(2017/06/09)
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- Diels-Alder reactions of five-membered heterocycles containing one heteroatom
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Diels-Alder reactions of five-membered heterocycles containing one heteroatom with an N-arylmaleimide were studied. Cycloaddition of 2,5-dimethylfuran (4) with 2-(4-methylphenyl)maleimide (3) in toluene at 60 °C gave bicyclic adduct 5. Cycloadditions of 3 with 2,5-dimethylthiophene (11) and 1,2,5-trimethylpyrrole (14) were also studied. Interestingly, the bicyclic compound 5 cleanly rearranged, with loss of water, when treated with p-toluenesulfonic acid in toluene at 80 °C to give 4,7-dimethyl-2-p-tolylisoindoline-1,3-dione (6).
- Ding, Xiaoyuan,Nguyen, Son T.,Williams, John D.,Peet, Norton P.
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supporting information
p. 7002 - 7006
(2015/01/09)
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- W(CO)5(L)-catalyzed cyclization of α-alkynyl-β- dicarbonyl derivatives: Synthesis of methylenelactones, furans, and methylenecyclopentanes
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W(CO)5(L)-Catalyzed cyclization of α-alkynyl-β-keto acids, keto esters, and diketones provides methylenelactones, furans, and methylenecyclopentanes via 5-exo-dig cyclization. Also, the present approach can be further applied to 5-endo-dig cycl
- Meng, Xiangjian,Kim, Sunggak
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experimental part
p. 1960 - 1964
(2012/09/25)
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- Iron(III)-catalyzed Conia-ene cyclization of 2-alkynic 1,3-dicarbonyl compounds
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A cheap, simple, and effective FeCl3-catalyzed Conia-ene cyclization of 2-alkynic 1,3-dicarbonyl compounds was stereospecific to afford alkylidenecyclopentanes in (E)-isomers via the 5-exo-dig pathway. The 5-endo-dig and 6-exo-dig cyclizations were also possible, depending on the structure of the substrates.
- Chan, Li Yan,Kim, Sunggak,Park, Youngchul,Lee, Phil Ho
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experimental part
p. 5239 - 5244
(2012/07/30)
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- Substituent-controlled electrocyclization of 2,4-dienones: Synthesis of 2,3,6-trisubstituted 2H-pyran-5-carboxylates and their transformations
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A facile access to 2,3,6-trisubstituted 2H-pyran-5-carboxylates is developed by employing 2-alkyl-2-enals as reactants with acetoacetates. The reaction involves Knoevenagel condensation followed by a 6π- electrocyclization, in which the presence of the C2 alkyl substituent in the enals favors the formation of (E)-Knoevenagel adducts for the ensuing electrocyclization. The resulting 2H-pyrans are hydrogenated to form 3,4-dihydro-2H-pyrans and converted into the endoperoxides by singlet-oxygen cycloaddition.
- Peng, Wei,Hirabaru, Toshiaki,Kawafuchi, Hiroyuki,Inokuchi, Tsutomu
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supporting information; experimental part
p. 5469 - 5474
(2011/11/06)
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- CuI-catalyzed intramolecular O-vinylation of carbonyl compounds
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The first copper-catalyzed intramolecular O-vinylation of carbonyl compounds with vinyl bromides was reported, among which the efficient formation of 5-, 6- and even 7-membered cyclic alkenyl ethers was achieved with β-ketoesters as nucleophiles. The Royal Society of Chemistry 2005.
- Fang, Yewen,Li, Chaozhong
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p. 3574 - 3576
(2007/10/03)
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- Polymer-supported selenium-induced electrophilic cyclization: Solid-phase synthesis of poly-substituted dihydrofurans and tetrahydrofurans
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Poly-substituted dihydrofurans and tetrahydrofurans have been synthesized through polymer-supported selenium-induced intramolecular electrophilic cyclization, followed by selenoxide syn-elimination or novel nucleophilic substitution cleavage of selenium resin with good yields and purities. Graphical Abstract
- Tang,Huang, Xian,Xu, Wei-Ming
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p. 9963 - 9969
(2007/10/03)
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- Sequential alkylation/transition metal catalysed annulation reactions of 1,3-dicarbonyl compounds with propargyl bromide
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β-Diketones, β-ketoesters and βketonitriles in the presence of propargyl bromide, DBU and a catalytic amount of CuI in toluene give 2,3,5-trisubstituted furans through sequential alkylation/cyclisation/isomerisation reactions. (C) 2000 Elsevier Science Ltd.
- Arcadi,Cerichelli,Chiarini,Di Giuseppe,Marinelli
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p. 9195 - 9198
(2007/10/03)
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- The reactions of diazo compounds with lactones. Part 2. The reaction of cyclic 2-diazo-1,3-dicarbonyl compounds with diketene: Benzofuran formation
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Cyclic 2-diazo-1,3-dicarbonyl compounds react with diketene in the presence of rhodium(II) salts to give benzofurans as the major isolated products. The formation of intermediate products with exocyclic double bonds which isomerise to benzofurans provides support for the proposed mechanism which involves initial formation of a dioxaspirooctenone by a formal dipolar cycloaddition reaction of a carbenoid to the exocyclic double bond of diketene followed by the loss of carbon dioxide. Acyclic 2-diazo-1,3-dicarbonyl compounds give furans in poor yield.
- Murphy, Paul V.,O'Sullivan, Timothy J.,Kennedy, Bryan D.,Geraghty, Niall W.A.
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p. 2121 - 2126
(2007/10/03)
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- Elimination Reactions of Terminal β-Oxy Selenoxides. Synthesis of Aryl and Vinyl Enol Ethers and of Furans, Oxazoles, and Thiazoles
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Elimination reactions of terminal selenoxides holding an alkoxy group in the β-position, RCH(OR)CH2SeOPh, are usually difficult and can give rise to complex reaction mixtures.We report that these reactions take place more easily whenever the oxygen atom is linked to an unsaturated group (-CH=CHR, -Ar, -CR=O, -CH=NR).These selenoxides are easily available, and the elimination reaction was employed to effect useful syntheses of both open-chain and cyclic aryl and vinyl enol ethers.Moreover, by simple isomerization with acids or bases the cyclic derivatives can be transformed into the corresponding furans.The same procedure has been employed to synthesize substituted oxazoles and thiazoles also.
- Tiecco, Marcello,Testaferri, Lorenzo,Tingoli, Marco,Marini, Francesca
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p. 1349 - 1354
(2007/10/02)
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- Preparation of 2,5-dimethylfuran-3-carboxylic acid alkyl esters
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A process for the preparation of a 2,5-dimethylfuran-3-carboxylic acid ester from an α-acyloxypropionaldehyde and an acetoacetic acid ester in the presence of anhydrous iron-III chloride.
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