- Iridium-catalyzed highly chemoselective and efficient reduction of nitroalkenes to nitroalkanes in water
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An iridium-catalyzed highly chemoselective and efficient transfer hydrogenation reduction of structurally diverse nitroalkenes was realized at very low catalyst loading (S/C = up to 10000 or 20?000), using formic acid or sodium formate as a traceless hydride donor in water. Excellent functionality tolerance is also observed. The turnover number and turnover frequency of the catalyst reach as high as 18?600 and 19?200 h-1, respectively. An inert atmosphere protection is not required. The reactivities of nitroalkenes are dependent on their substitution pattern, and the pH value is a key factor to accomplish the complete conversion and excellent chemoselectivity. Purification of products is achieved by simple extraction without column chromatography. The reduction procedure is facilely amplified to 10 g scale at 10?000 S/C ratio. The potential of this green reduction in enantioselective hydrogenation has been demonstrated.
- Chen, Yang,Liu, Changmeng,Xu, Dong,Xu, Jiaxi,Yang, Zhanhui
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supporting information
p. 6050 - 6058
(2021/08/23)
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- Enantioselective hydrogenation of α,β-disubstituted nitroalkenes
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The first highly chemo- and enantioselective hydrogenation of α,β-disubstituted nitroalkenes was accomplished with rhodium/JosiPhos-J2 as a catalyst, with the yield and enantioselectivity of up to 95% and 94%, respectively. The α-chiral nitroalkanes will provide an entry to valuable chiral amphetamines which are otherwise not so easily accessed. This journal is the Partner Organisations 2014.
- Li, Shengkun,Huang, Kexuan,Zhang, Xumu
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p. 8878 - 8881
(2014/08/05)
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- The highly chemoselective transfer hydrogenation of the carbon-carbon double bond of conjugated nitroalkenes by a rhodium complex
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Chemoselective transfer hydrogenation of conjugated nitroalkenes catalyzed by [RhCl2Cp·]2-diamine complex (Cp ·=η5-C5Me5) using HCOOH/Et3N (5:2) (TEAF) as a hydrogen source was realized. A variety of nitrostyrenes, β-methyl nitrostyrenes, and 3-methyl-4-nitro-5-alkenyl- isoxazoles were reduced smoothly in good to excellent yields in short reaction time. Other functional groups are inert under the reaction conditions.
- Xiang, Jing,Sun, Er-Xiao,Lian, Chun-Xia,Yuan, Wei-Cheng,Zhu, Jin,Wang, Qiwei,Deng, Jingen
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experimental part
p. 4609 - 4620
(2012/07/28)
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- 2-Benzyl-2-methyl-2H-benzimidazole 1,3-dioxide derivatives: Spectroscopic and theoretical study
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The spectroscopic behavior of 2-benzyl-2-methyl-2H-benzimidazole 1,3-dioxide derivatives in solution was studied in terms of electronic and nuclear magnetic resonance (1H and 13C NMR) techniques. The experimental spectra were compared to the theoretical ones, obtained at DFT level, proving that the compounds adopt in solution a bird-like conformational distribution. Also, theoretically this conformational distribution resulted the most stable in gas phase. Infrared spectroscopy was used to study solid state behavior identifying experimentally the N-O stretching near to 1380, 1365 and 1225 cm-1 and the vibrational benzimidazole skeleton near to 1610 and 1590 cm-1. The vibrational spectrum was satisfactorily described by DFT calculations funding the N-O stretching as a coupled vibration near to 1470, 1350 and 1285 cm-1. The fragmentation that takes place in mass spectrometry was assigned for all of the new derivatives.
- Merlino, Alicia,Boiani, Mariana,Cerecetto, Hugo,Gonzalez, Mercedes
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p. 540 - 549
(2008/02/07)
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- Borrowing hydrogen: Iridium-catalysed reactions for the formation of C-C bonds from alcohols
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Alcohols have been employed as substrates for C-C bond-forming reactions which involve initial activation by the temporary removal of hydrogen to form an aldehyde. The intermediate aldehyde is converted into an alkene via a Horner-Wadsworth-Emmons reaction, nitroaldol and aldol reactions. The 'borrowed hydrogen' is then returned to the alkene to form a C-C bond. The Royal Society of Chemistry 2006.
- Black, Phillip. J.,Cami-Kobeci, Gerta,Edwards, Michael G.,Slatford, Paul A.,Whittlesey, Michael K.,Williams, Jonathan M. J.
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p. 116 - 125
(2007/10/03)
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- Asymmetric reduction of nitroalkenes with baker's yeast
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Various α,β-disubstituted and trisubstituted nitroalkenes were chemoselectively reduced with baker's yeast to the corresponding nitroalkanes. Stereoselectivities of the reduction of α,β-disubstituted nitroalkenes were modest to low, and e.e.s up to 52% were obtained. Trisubstituted nitroalkenes could be reduced to the corresponding nitroalkanes with excellent enantioselectivities, moderate diastereoselectivities and in good yield.
- Kawai, Yasushi,Inaba, Yoshikazu,Tokitoh, Norihiro
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p. 309 - 318
(2007/10/03)
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- REDUCTION OF AROMATIC NITROALKENES WITH BAKER'S YEAST
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Aromatic nitroalkenes were reduced chemoselectively with baker's yeast to give the corresponding nitroalkanes.
- Takeshita, Mitsuhiro,Yoshida, Sachiko,Kohno, Yoichiro
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p. 553 - 562
(2007/10/02)
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