- Synthesis of Unsymmetrical 1,4-Dicarbonyl Compounds by Photocatalytic Oxidative Radical Additions
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Herein we report a photocatalytic oxidative radical addition reaction for the synthesis of unsymmetrical 1,4-dicarbonyl compounds. This reaction utilizes a desulfurization process to generate electrophilic radicals, which add to α-halogenated alkenes and undergo further oxidation to deliver 1,4-dicarbonyl compounds. This mild and highly efficient method provides a valuable alternative to known strategies.
- Dong, Ya,Li, Ruining,Zhou, Junliang,Sun, Zhankui
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supporting information
p. 6387 - 6390
(2021/08/23)
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- Palladium-Catalyzed Synthesis of Deuterated Alkenes through Deuterodechlorination of Alkenyl Chlorides
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The palladium-catalyzed deuterodechlorination of alkenyl chlorides has been developed, and a variety of deuterated alkenes were synthesized with precise control of the deuterium incorporation. This catalytic process tolerates heterocyclic moieties and frameworks derived from bioactive agents. In addition to the double incorporation of deuterium, the gram-scale synthesis of a deuterated iminostilbene unit including a core substructure of carbamazepine was achieved in a high yield with an excellent degree of deuteration.
- Kuriyama, Masami,Yano, Gemba,Kiba, Hirotoshi,Morimoto, Tetsuro,Yamamoto, Kosuke,Demizu, Yosuke,Onomura, Osamu
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supporting information
p. 1552 - 1557
(2019/08/08)
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- Partial Reduction and Selective Transfer of Hydrogen Chloride on Catalytic Gold Nanoparticles
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HCl in solution accepts electron density from Au NPs and partially reduces at room temperature, as occurs with other simple diatomic molecules, such as O2 and H2. The activation can be run catalytically in the presence of alkynes to give exclusively E-vinyl chlorides, after the regio- and stereoselective transfer of HCl. Based also on this method, vinyl chloride monomer (VCM) can be produced in a milder and greener way than current industrial processes.
- Oliver-Meseguer, Judit,Doménech-Carbó, Antonio,Boronat, Mercedes,Leyva-Pérez, Antonio,Corma, Avelino
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supporting information
p. 6435 - 6439
(2017/05/29)
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- Chloride-tolerant gold(I)-catalyzed regioselective hydrochlorination of alkynes
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We have developed a highly regioselective homogeneous gold(I)-catalyzed anti-hydrochlorination of unactivated alkynes at room temperature. We have overcome the incompatibility between conventional cationic gold catalysts and chloride by using a hydrogen-b
- Ebule, Rene,Liang, Shengzong,Hammond, Gerald B.,Xu, Bo
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p. 6798 - 6801
(2017/11/09)
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- Catalyst-free hydrochlorination protocol for terminal arylalkynes with hydrogen chloride
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We present a simple and straightforward protocol for hydrochlorination of terminal arylalkynes to vinyl chlorides using hydrogen chloride under mild reaction conditions. This protocol does not involve any metal catalysts or additives. It is simple, inexpensive, and easy to prepare, and exhibits good reaction activity. The hydrochlorination proceeds smoothly to yield unique regioselective products via the Markovnikov addition rule.
- Xu, Cai-Xia,Ma, Cun-Hua,Xiao, Fu-Rong,Chen, Hong-Wei,Dai, Bin
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supporting information
p. 1683 - 1685
(2016/11/12)
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- Green and Efficient: Iron-Catalyzed Selective Oxidation of Olefins to Carbonyls with O2
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A mild and operationally simple iron-catalyzed protocol for the selective aerobic oxidation of aromatic olefins to carbonyl compounds is described. Catalyzed by a Fe(III) species bearing a pyridine bisimidazoline ligand at 1 atm of O2, α- and β-substituted styrenes were cleaved to afford benzaldehydes and aromatic ketones generally in high yields with excellent chemoselectivity and very good functional group tolerance, including those containing radical-sensitive groups. With α-halo-substituted styrenes, the oxidation took place with concomitant halide migration to afford α-halo acetophenones. Various observations have been made, pointing to a mechanism in which both molecular oxygen and the olefinic substrate coordinate to the iron center, leading to the formation of a dioxetane intermediate, which collapses to give the carbonyl product. (Chemical Equation).
- Gonzalez-De-Castro, Angela,Xiao, Jianliang
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p. 8206 - 8218
(2015/07/15)
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- Synthesis of Vinyl Chlorides via Triphosgene-Pyridine Activation of Ketones
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Herein, we describe a mild method to prepare aliphatic and aromatic vinyl chlorides from their corresponding ketones via triphosgene-pyridine activation in dichloromethane at reflux. The mechanism of this reaction is proposed to involve formation of a put
- Saputra, Mirza A.,Ngo, Ly,Kartika, Rendy
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p. 8815 - 8820
(2015/09/15)
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- A very simple synthesis of chloroalkenes and chlorodienes by selective Suzuki couplings of 1,1- and 1,2-dichloroethylene
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Chloroalkenes, important building blocks for cross-coupling reactions, are prepared in one step by the Suzuki reaction of 1,1-dichloroethylene and 1,2-dichloroethylene with alkenyl- and arylboronic acids. Under the proper reaction conditions, it is possible to obtain the monocoupling reaction to provide the corresponding chloroalkenes with good yields. This method represents an excellent route for the preparation of chloroalkenes and chlorodienes from commercially available starting materials.
- Barluenga, Jose,Moriel, Patricia,Aznar, Fernando,Valdes, Carlos
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p. 347 - 353
(2007/10/03)
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- One-step synthesis of aromatic terminal alkynes from their corresponding ketones under microwave irradiation
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One-step microwave-assisted synthesis of phenylacetylenes 2a-j from the corresponding ketones 1a-j in the presence of a new reagent, PCl 5 -pyridine, is described. The reaction is carried out under a simple operational and experimental procedure, avoiding the use of the complicated and harsh multistep reaction. Copyright Taylor & Francis Group, LLC.
- Ghaffarzadeh, Mohammad,Bolourtchian, Mohammad,Fard, Zohreh,Halvagar, Mohammad,Mohsenzadeh, Farshid
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p. 1973 - 1981
(2007/10/03)
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- Vinylcations, 39. Zinc Chloride Catalysed Addition of Hydrogen Chloride to Cyclopropylalkynes
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Zinc chloride catalysed addition of hydrogen chloride to 1-cyclopropylalkynes 5a-e (R = CH3, c-C3H5, phenyl, p-tolyl, 4-methoxyphenyl) is studied and the results are compared with those of the addition of HCl/ZnCl2 to several substituted arylalkynes 10a-h.Thus, the alkynes are reacted with HCl/ZnCl2 in dichloromethane and the reaction products are investigated also with respect to their stereochemistry.All alkynes yield predominantly the direkt hydrogen chloride addition products.The 1-cyclopropylalkynes 5a-d give (E)-1-chloro-1-cyclopropyl-1-alkenes 15, and (E)-1-chloro-2-cyclopropyl-1-(4-methoxyphenyl)ethene (16e) is obtained as the major product from 5e (R = 4-CH3OC6H4).Moreover, ring opening to homoallenyl chlorides 19 and, as a side reaction, formation of the ketones 17 and 18 by the addition of water are observed.In a secondary addition reaction, the dichlorides 20 are also obtained by homoallyl rearrangement.The arylalkynes 10a-g react preferentially with formation of (E)-1-aryl-1-chloroalkenes 21.Relative rates are obtained by inter- and intramolecular competition reactions of the alkynes 23 and 5b-e with HCl/ZnCl2 showing the order of stabilization by substituents of the intermediate vinyl cation 2 to be 4-ClC6H4 E2 mechanism.The preferential formation of the addition products E-15, E-16, and E-21 is attributed to a syn-vinyl cation ion pair and to steric approach control of the β-substituents in the vinyl cation intermediate 2.
- Hanack, Michael,Weber, Erhard
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p. 777 - 797
(2007/10/02)
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