- Method for synthesizing beta-bromostyrene through metal-free catalysis
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The invention discloses a method for synthesizing beta-bromostyrene through metal-free catalysis, and belongs to the technical field of organic chemistry. Substituted styrene 1 is used as a raw material and is reacted in the presence of a bromination reagent, sodium persulfate and dichloroethane, and the beta-bromostyrene compound 2 can be obtained in one step. The method is capable of solving thetechnical problem that in the traditional synthesis method, conversion into alkenyl boron, alkenyl silicon and other intermediates under the catalysis of noble metals and then further halogenation are needed; the defects of expensive reaction reagent, high catalytic cost, complex operation, incapability of large-scale preparation and the like in the traditional preparation method are avoided; byadopting the method, a series of beta-bromostyrene compounds can be obtained, and the method has a potential application prospect.
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Paragraph 0055-0057
(2020/02/06)
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- Facile Synthesis of β-Bromostyrenes by Direct Bromination of Styrenes with N -Bromosuccinimide and Sodium Persulfate
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A new, direct, efficient, and transition-metal-free method is reported for the synthesis of β-bromostyrenes from styrenes by using N -bromosuccinimide as the brominating reagent and sodium persulfate (Na 2S 2O 8) as the oxidant. This convenient and concise reaction is practical, operationally simple, and can be adapted for large-scale syntheses.
- Chen, Xuenian,Gao, Yan,Jing, Yi,Ma, Yan-Na,Zhao, Qianyi
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supporting information
(2020/09/09)
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- Decarboxylative bromination of α,β-unsaturated carboxylic acids via an anodic oxidation
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A novel bromination of α,β-unsaturated carboxylic acids was developed via a decarboxylation by virtue of a direct anodic electro-oxidation. In this method, ammonium bromide was employed as a bromine source and the reaction features transition-metal-free, short time, and no additional supporting electrolyte.
- Bi, Mei-Xiang,Qian, Peng,Wang, Yu-Kang,Zha, Zheng-Gen,Wang, Zhi-Yong
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p. 1159 - 1162
(2017/06/19)
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- Ohmic Heating and Ionic Liquids in Combination for the Indium-Promoted Synthesis of 1-Halo Alkenyl Compounds: Applications to Pd-Catalysed Cross-Coupling Reactions
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We have explored the combination of ohmic heating (ΩH) with ionic liquids for indium-promoted reactions and report herein the indium-promoted dehalogenation of gem-dibromo alkenes and the indium-mediated reductive elimination of chlorohydrins for the synthesis of 1-halo alkenyl derivatives. Heck, Stille, Suzuki, Kumada and Sonogashira couplings of the resulting 1-halo-1-alkenes with appropriate reagents were carried out to give alkenes, dienes and enynes. We report herein the combination of ohmic heating (ΩH) with ionic liquids for the indium-promoted dehalogenation of gem-dibromo alkenes and the indium-mediated reductive elimination of chlorohydrins. The 1-halo alkenyl derivatives synthesized were then submitted to a series of cross-coupling reactions to give conjugated alkenes, dienes and enynes.
- Soengas, Raquel G.,Silva, Vera L. M.,Pinto, Joana,Rodríguez-Solla, Humberto,Silva, Artur M. S.
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- Metal-Mediated Debromination of gem-Dibromoalkenes under Mild Conditions
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We describe the facile and efficient metal-promoted reduction of C-Br bonds of gem-dibromides. When the reaction is mediated by indium, the corresponding vinyl bromides are obtained in good yields and high E-stereoselectivities. Alternatively, when the reduction is mediated by samarium diiodide, vinyl bromides are obtained in moderate yields and good Z-selectivities.
- Soengas, Raquel G.,Rodríguez-Solla, Humberto,Silva, Artur M.S.
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supporting information
p. 1096 - 1099
(2016/05/19)
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- Palladium(0)-Catalyzed Methylcyclopropanation of Norbornenes with Vinyl Bromides and Mechanism Study
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An unusual methylcyclopropanation from [2 + 1] cycloadditions of vinyl bromides to norbornenes catalyzed by Pd(OAc)2/PPh3 in the presence of CH3ONa and CH3OH has been established. A methylcyclopropane subunit was installed by a 3-fold domino procedure involving a key protonation course. Preliminary deuterium-labeling studies revealed that the proton came from methyl of CH3OH and also exposed an additional hydrogen/deuterium exchange process. These two proton-concerned reactions were fully chemoselective.
- Mao, Jiangang,Xie, Hujun,Bao, Weiliang
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supporting information
p. 3678 - 3681
(2015/08/18)
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- Palladium(0)-catalyzed methylenecyclopropanation of norbornenes with vinyl bromides
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Highly strained methylenecyclopropane derivatives have been achieved via a novel and efficient Pd(0)-catalyzed domino reaction. The formal [2 + 1] cycloaddition reaction of vinyl bromides to norbornenes involves a Heck-type coupling and a C(sp2)-H bond activation.
- Mao, Jiangang,Bao, Weiliang
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supporting information
p. 2646 - 2649
(2014/06/09)
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- H-β-zeolite catalyzed synthesis of β-bromostyrenes from styrene bromohydrins
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Synthesis of β-bromostyrenes from styrene bromohydrins using H-β-zeolite as catalyst under moderate conditions is reported. The catalyst could be regenerated and reused up to three consecutive cycles.
- Pappula, Venkatanarayana,Donthiri, Ramachandra Reddy,Darapaneni, Chandra Mohan,Subbarayappa, Adimurthy
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supporting information
p. 1793 - 1795
(2014/03/21)
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- Stereoselective synthesis of (Z)-β-arylvinyl bromides from anti-2,3-dibromo-3-arylpropanoic acids
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A novel method for the stereoselective synthesis of (Z)-β-arylvinyl bromides in excellent yields by debrominative decarboxylation of anti-2,3-dibromo-3-arylpropanoic acids using NaN3 was developed. This facile transformation was achieved under room temperature for 1-2 h.
- Xv, Wenjing,Zhang, Wensheng,Zhang, Fei,Kuang, Chunxiang
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p. 115 - 117
(2014/03/21)
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- Synthesis and biological evaluation of polyenylpyrrole derivatives as anticancer agents acting through caspases-dependent apoptosis
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A class of polyenylpyrroles and their analogues were designed from a hit compound identified in a fungus. The compounds synthesized were evaluated for their cell cytotoxicity against human non-small-cell lung carcinoma cell lines A549. Two compounds were found to exhibit high cytotoxicity against A549 cells with IC50 of 0.6 and 0.01 μM, respectively. The underlying mechanisms for the anticancer activity were demonstrated as caspases activation dependent apoptosis induction through loss of mitochondrial membrane potential, release of cytochrome c, increase in B-cell lymphoma-2-associated X protein (Bax) level, and decrease in B-cell lymphoma-2 (Bcl-2) level. The two compounds were nontoxic to normal human lung Beas-2b cells (IC50 > 80 μM), indicating that they are highly selective in their cytotoxicity activities. Furthermore, one compound showed in vivo anticancer activity in human-lung-cancer-cell-bearing mice. These results open promising insights on how these conjugated polyenes mediate cytotoxicity and may provide a molecular rationale for future therapeutic interventions in carcinogenesis.
- Fang, Zhanxiong,Liao, Pei-Chun,Yang, Yu-Liang,Yang, Feng-Ling,Chen, Yi-Lin,Lam, Yulin,Hua, Kuo-Feng,Wu, Shih-Hsiung
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supporting information; experimental part
p. 7967 - 7978
(2011/03/19)
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- 2-(2-Haloalkenyl)-aryl halides as substrates for palladium-catalysed tandem C-N bond formation: Efficient synthesis of 1-substituted indoles
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2-(2-Haloalkenyl)-aryl halides, conveniently prepared in a single step from the corresponding o-halobenzaldehydes, are combined with amines under Pd catalysis to provide 1-substituted indoles. All combinations of Br and Cl leaving groups can be employed,
- Willis, Michael C.,Brace, Gareth N.,Findlay, Thomas J. K.,Holmes, Ian P.
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p. 851 - 856
(2007/10/03)
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- Synthesis of (Z)-1-bromo-1-alkenes and terminal alkynes from anti-2,3-dibromoalkanoic acids by microwave-induced reaction
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(Z)-1-Bromo-1-alkenes were stereoselectively prepared in high yields in a short reaction time by microwave irradiation of the corresponding anti-2,3-dibromoalkanoic acids in a Et3N/DMF system. A one-pot synthesis of terminal alkynes and enynes from 2,3-dibromoalkanoic acids were also developed by microwave-induced reaction.
- Kuang, Chunxiang,Yang, Qing,Senboku, Hisanori,Tokuda, Masao
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p. 4043 - 4052
(2007/10/03)
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- A one-pot synthesis of terminal alkynes from anti-3-aryl-2,3- dibromopropanoic acids under microwave irradiation
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A facile one-pot synthesis of terminal alkynes was achieved by microwave irradiation of a mixture of anti-3-aryl-2,3-dibromopropanoic acids, Et 3N and DMF and subsequent irradiation in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). This method requires short reaction time (1-2 min) and gives terminal alkynes in high yields. Copyright
- Kuang, Chunxiang,Senboku, Hisanori,Tokuda, Masao
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