- A rapid and efficient method for the reduction of quinoxalines
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Mono and di-substituted alkyl and aryl quinoxalines are rapidly reduced in high yield to their respective 1,2,3,4-tetrahydro-derivatives by borane in THF solution. In the case of the 2,3-di-substituted compounds, reduction is stereoselective yielding excl
- McKinney, Andrew M.,Jackson, Kevin R.,Salvatore, Ralph Nicholas,Savrides, Elena-Maria,Edatte, Mary Jane,Gavin, Terrence
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- Transfer hydrogenation of nitrogen heterocycles using a recyclable rhodium catalyst immobilized on bipyridine-periodic mesoporous organosilica
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Transfer hydrogenation of unsaturated nitrogen heterocycles using a rhodium catalyst immobilized on bipyridine-periodic mesoporous organosilica (BPy-PMO) is described. The immobilized catalyst was prepared by mixing [Cp?RhCl2]2 (Cp?
- Matsui, Kazuma,Maegawa, Yoshifumi,Waki, Minoru,Inagaki, Shinji,Yamamoto, Yoshihiko
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p. 534 - 539
(2018/02/07)
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- Asymmetric Transfer Hydrogenations of 2,3-Disubstituted Quinoxalines with Ammonia Borane
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An asymmetric transfer hydrogenation of 2,3-disubstituted quinoxalines using a chiral frustrated Lewis pair of Piers' borane and (R)-tert-butylsulfinamide as the catalyst with ammonia borane as the hydrogen source has been successfully realized. For 2-alk
- Li, Songlei,Meng, Wei,Du, Haifeng
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p. 2604 - 2606
(2017/05/24)
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- Tris(pentafluorophenyl)borane-Catalyzed Acceptorless Dehydrogenation of N-Heterocycles
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Catalytic acceptorless dehydrogenation is an environmentally benign way to desaturate organic compounds. This process is traditionally accomplished with transition-metal-based catalysts. Herein, a borane-catalyzed, metal-free acceptorless dehydrogenation of saturated N-heterocycles is disclosed. Tris(pentafluorophenyl)borane was identified as a versatile catalyst, which afforded several synthetically important N-heteroarenes in up to quantitative yield. Specifically, the present metal-free catalytic system exhibited a uniquely high tolerance toward sulfur functionalities, and demonstrated superior reactivity in the synthesis of benzothiazoles compared to conventional metal-catalyzed systems. This protocol can thus be regarded as the first example of metal-free acceptorless dehydrogenation in synthetic organic chemistry.
- Kojima, Masahiro,Kanai, Motomu
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supporting information
p. 12224 - 12227
(2016/10/13)
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- A highly cis-selective and enantioselective metal-free hydrogenation of 2,3-disubstituted quinoxalines
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A wide range of 2,3-disubstituted quinoxalines have been successfully hydrogenated with H2 using borane catalysts to produce the desired tetrahydroquinoxalines in 80-99% yields with excellent cis selectivity. Significantly, the asymmetric reaction employing chiral borane catalysts generated by the in situ hydroboration of chiral dienes with HB(C6F5)2 under mild reaction conditions has also been achieved with up to 96% ee, and represents the first catalytic asymmetric system to furnish optically active cis-2,3-disubstituted 1,2,3,4-tetrahydroquinoxalines.
- Zhang, Zhenhua,Du, Haifeng
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p. 623 - 626
(2015/03/04)
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- Titanium(III) Chloride and Electrochemical Reduction of Pyrazine, Quinoxaline and Triazine Derivatives and of their Salts
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The reduction of pyrazine, quinoxaline and triazine derivatives by titanium(III) chloride leads to di- or tetrahydrogenated compounds.High yields of tetrahydro compounds are also obtained through the reduction of quinoxalinium salts.These results are comp
- Armand, J.,Chekir, K.,Pinson, J.
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p. 1237 - 1240
(2007/10/02)
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