- Copper-Catalyzed Dehydrogenative Diels-Alder Reaction
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A practical and effective copper-catalyzed dehydrogenative Diels-Alder reaction of gem-diesters and ketone with dienes has been established. The active dienophiles were generated in situ via a radical-based dehydrogenation process, which reacted with a wide variety of dienes to afford various polysubstituted cyclohexene derivatives in good to excellent yields.
- Jiang, Bing,Liang, Qiu-Ju,Han, Yu,Zhao, Meng,Xu, Yun-He,Loh, Teck-Peng
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p. 3215 - 3219
(2018/06/11)
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- Preparation method of conjugated diene compound
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The invention belongs to the field of fine chemicals and relevant chemical technologies and provides a preparation method of a butadiene derivative. The preparation method comprises the following steps of by taking phenylacetylene and a derivative thereof as raw materials, under the actions of a metal catalyst and an additive, performing reaction in an anhydrous organic solvent, and converting thephenylacetylene and the derivative thereof to a 2,3-di-substituted-1,3-butadiene compound. The preparation method has the beneficial effects of being simple and convenient to operate and mild in condition, being environmental friendly, having the possibility of realizing industrialization, and preparing the butadiene compound with a higher yield. The butadiene compound synthesized by utilizing the method can perform further functionalization to obtain various compounds, and then the compounds are applied to development and study of natural products, functional materials and the fine chemicals.
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Paragraph 0038; 0041; 0042; 0043; 0044
(2018/04/01)
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- From propargylic biscarbonate to diaryl[n]dendralenes
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An efficient cross-coupling reaction using a low cost carbon-supported palladium (Pd/C) catalyst for the synthesis of cross-conjugated compounds, diaryl[n]dendralenes, has been developed. The reaction of a propargylic biscarbonate with phenylboronic acid using Pd/C and phosphine ligand (S-Phos) gave 2,3-diphenyl[2]dendralene in high yield. We found that Pd/C was an effective catalyst for the synthesis of dialyl[n]dendralenes. The synthesis of various dendralenes was successfully achieved under the optimized conditions, giving dialyl [2] and [4] dendralenes in good yields.
- Hayashi, Shotaro,Kasuya, Masakatsu,Machida, Junsuke,Koizumi, Toshio
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p. 2429 - 2432
(2017/06/01)
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- Solid Acid-Catalyzed Dehydration of Pinacol Derivatives in Ionic Liquid: Simple and Efficient Access to Branched 1,3-Dienes
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The selective dehydration of pinacol derivatives to branched 1,3-dienes is extremely challenging because of the predominance of pinacol rearrangement. Herein, we successfully achieve this goal by employing a recyclable solid acid/ionic liquid catalyst system. The dehydration of alkyl- and cycloalkyl-derived diols in an Amberlyst-15/[Emim]Cl system afforded the corresponding 1,3-dienes in good yields, while a Nafion/[Emim]Cl system was demonstrated to be a better catalyst system for the dehydration of aryl-substituted substrates. Our protocol features straightforward and simple access to branched 1,3-dienes, high chemoselectivity, a recyclable catalyst system, a facile separation of dienes just by decantation, and a broad substrate scope.
- Hu, Yancheng,Li, Ning,Li, Guangyi,Wang, Aiqin,Cong, Yu,Wang, Xiaodong,Zhang, Tao
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p. 2576 - 2582
(2017/05/31)
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- Quinonediimines as redox-active organocatalysts for oxidative coupling of aryl- and alkenylmagnesium compounds under molecular oxygen
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It is revealed that N,N′-diphenyl-p-benzoquinonediimine works as a redox-active organocatalyst for the oxidative homo-coupling of aryl- and alkenylmagnesium compounds under molecular oxygen. The catalytic cycle was formally monitored by 1H NMR experiments.
- Amaya, Toru,Suzuki, Riyo,Hirao, Toshikazu
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p. 7790 - 7793
(2016/07/06)
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- Pd-catalyzed cross-coupling reactions of hydrazones: Regioselective synthesis of highly branched dienes
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The regioselective formation of highly branched dienes is a challenging task. Design and exploration of alternative working models to achieve such a regioselectivity to accomplish highly branched dienes is considered to be a historical advancement of Heck reaction to construct branched dienes. On the basis of the utility of carbene transfer reactions, in the reaction of hydrazones with Pd(II) under oxidative conditions, we envisioned obtaining a Pd-bis-carbene complex with α-hydrogens, which can lead to branched dienes. Herein, we report a novel Pd-catalyzed selective coupling reaction of hydrazones in the presence of t-BuOLi and benzoquinone to form the corresponding branched dienes. The utility of the Pd catalyst for the cross-coupling reactions for synthesizing branched conjugated dienes is rare. The reaction is very versatile and compatible with a variety of functional groups and is useful in synthesizing heterocyclic molecules. We anticipate that this Pd-catalyzed cross-coupling reaction will open new avenues for synthesizing useful compounds.
- Ojha, Devi Prasan,Prabhu, Kandikere Ramaiah
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p. 12136 - 12143
(2014/01/06)
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- Facile synthesis of dibranched conjugated dienes via palladium-catalyzed oxidative coupling of N-tosylhydrazones
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A facile and highly regioselective Pd-catalyzed oxidative coupling of N-tosylhydrazones providing efficient access to 2,3-disubstituted-1,3-butadienes has been developed. This process features readily available starting materials and mild reaction conditions. Further transformations of the obtained dibranched 1,3-dienes, through Diels-Alder reactions and indene synthesis, are also demonstrated, which reveal their great potential for synthetic utility.
- Jiang, Huanfeng,He, Li,Li, Xianwei,Chen, Huoji,Wu, Wanqing,Fu, Wei
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supporting information
p. 9218 - 9220
(2013/09/24)
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- Synthesis of indenes via Bronsted acid catalyzed cyclization of diaryl- and alkyl aryl-1,3-dienes
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Substituted indenes can be synthesized via the Bronsted acid catalyzed cyclization of diaryl- and alkyl aryl-1,3-dienes. In this approach, treatment of symmetric or unsymmetric diaryl- and alkyl aryl-1,3-dienes with a catalytic amount of trifluoromethanesulfonic acid gives a variety of indene derivatives in good to excellent yields under mild conditions.
- Eom, Dahan,Park, Sangjune,Park, Youngchul,Ryu, Taekyu,Lee, Phil Ho
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supporting information
p. 5392 - 5395,4
(2012/12/12)
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- Synthesis of indenes via Br?nsted acid catalyzed cyclization of diaryl- and alkyl aryl-1,3-dienes
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Substituted indenes can be synthesized via the Br?nsted acid catalyzed cyclization of diaryl- and alkyl aryl-1,3-dienes. In this approach, treatment of symmetric or unsymmetric diaryl- and alkyl aryl-1,3-dienes with a catalytic amount of trifluoromethanesulfonic acid gives a variety of indene derivatives in good to excellent yields under mild conditions.
- Eom, Dahan,Park, Sangjune,Park, Youngchul,Ryu, Taekyu,Lee, Phil Ho
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supporting information
p. 5392 - 5395
(2013/01/15)
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- Direct one-pot synthesis of 2,3-diarylbuta-1,3-diene via self-coupling of acetophenones
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A mild and straightforward route to 2,3-diarylbuta-1,3-diene is described here. By treatment with SmI2-Ac20, acetophe-none and its analogues underwent self-coupling reactions and subsequent elimination to give a series of 2,3-diarylbuta-1,3-dienes in moderate to good yields.
- Li, Jian,Li, Shaoyu,Jia, Xueshun
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experimental part
p. 1529 - 1531
(2009/04/07)
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- SYNTHESES WITH DIKETO SELENIDES
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We report a) a modified synthesis of diketo selenides, b) preparation of 2,5-diacylselenophenes by condensation of diketoselenides with glyoxal, c) preparation of poly-substituted selenophenes by intramolecular reductive coupling reaction of diketo selenides with low-valent titanium reagent under controlled conditions (0 degC) followed by dehydratation of the resulting 3,4-dihydroxyselenolanes, and d) formation of 2,5-dihydroselenophenes and 1,3-dienes by treatment of diketo selenides with the low-valent titanium reagent in refluxing tetrahydrofuran.
- Nakayama, Juzo,Shibuya, Masahiro,Ikuina, Yoji,Murai, Fumito,Hoshino, Masamatsu
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p. 149 - 156
(2007/10/02)
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- Formation of 2,5-Dihydroselenophenes and 1,3-Dienes from Diketo Selenides by Reduction with Low-valent Titanium Reagents
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Reduction of a series of diketo selenides with a low-valent titanium reagent affords 2,5-dihydroselenophenes and 1,3-dienes in comparable yields.
- Nakayama, Juzo,Ikuina, Yoji,Murai, Fumito,Hoshino, Masamatsu
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p. 1072 - 1073
(2007/10/02)
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- EFFICIENT PREPARATION OF POLYSUBSTITUTED 1,3-DIENES FROM α,α'-DIKETO SULFIDES
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A series of polysubstituted 1,3-dienes were prepared in good overall yields in three steps starting from readily accessible α,α'-diketo sulfides.
- Nakayama, Juzo,Machida, Haruki,Saito, Ryuji,Akimoto, Keiichi,Hoshino, Masamatsu
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p. 1173 - 1176
(2007/10/02)
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- NOVEL SYNTHESIS OF 2,3-DIARYLBUTA-1,3-DIENES FROM 1,4-DIMETHOXYBUTYNE-2
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It was found that 2,3-diarylbuta-1,3-dienes were readily obtained in good to excellent yields through the SN-2' type substitution of 1,4-dimethoxybutyne-2 with aryl Grignard reagents in the presence of a copper(I) salt.
- Ishino, Yoshio,Nishiguchi, Ikuzo,Takihira, Fujio,Hirashima, Tsuneaki
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p. 1527 - 1528
(2007/10/02)
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