- Regioselective N-1 and C-2 diacylation of 3-substituted indoles with arylglyoxal hydrates for the synthesis of indolyl diketones
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A highly regioselective N-1 and C-2 diacylation of 3-substituted indoles with arylglyoxal hydrates to afford N-1 and C-2 indolyl diketones in moderate to good yields is described. Notably, the control of regioselectivity is achieved by small changes in the Cu catalyst, additive and solvent. Importantly, the intermediates for N-1 and C-2 diacylation were detected and two plausible pathways were also proposed.
- Pan, Dalong,Chu, Jinpeng,Gao, Xianrui,Wang, Cuiping,Meng, Qingtao,Chi, Haijun,Dong, Yan,Duan, Chunying,Zhang, Zhiqiang
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supporting information
p. 6998 - 7003
(2018/10/17)
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- Naphthol synthesis: Annulation of nitrones with alkynes: Via rhodium(III)-catalyzed C-H activation
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An efficient and redox-neutral naphthol synthesis has been realized via rhodium(iii) catalyzed C-H activation of α-carbonyl nitrones and annulation with alkynes, where the nitrone group functioned as a traceless directing group.
- Wang, Qiang,Xu, Youwei,Yang, Xifa,Li, Yunyun,Li, Xingwei
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supporting information
p. 9640 - 9643
(2017/09/01)
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- Synthesis and X-ray Characterization of Alkali Metal 2-Acyl-1,1,3,3-tetracyanopropenides
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A novel route for synthesis of 2-acyl-1,1,3,3-tetracyanopropenides (ATCN) salts in high yields and excellent purities starting from readily available methyl ketones, malononitrile, bromine, and alkali metal acetates is reported. The starting aryl(heteroaryl) methyl ketones were oxidized to the corresponding α-ketoaldehydes by new a DMSO-NaBr-H2SO4 oxidation system in yields up to 90% within a short reaction time of 8-10 min. The subsequent stages of ATCN preparation are realized in aqueous media without use of any toxic solvents, in accordance with principle 5 of "green chemistry". Lithium, sodium, potassium, rubidium, and cesium 2-benzoyl-1,1,3,3-tetracyanopropenides were characterized by X-ray diffraction analysis. These salts show a good potential for synthesis of five- and six-membered heterocycles and may serve as potentially useful ligands in coordination and supramolecular chemistry.
- Karpov, Sergey V.,Grigor'Ev, Arthur A.,Kayukov, Yakov S.,Karpova, Irina V.,Nasakin, Oleg E.,Tafeenko, Victor A.
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p. 6402 - 6408
(2016/08/16)
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- Synthesis of 7-hydroxy-6,7-dihydro-indole and 6′,7′-dihydro-3,7′-biindole derivatives from domino reactions of arylglyoxals or methyl ketones with enamines
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A series of interesting 7-hydroxy-2-aryl-6,7-dihydro-indol-4(5H)-ones 3 was successfully synthesized in moderate to good yields by the domino reactions of different arylglyoxals 1 with enamines 2 under catalyst-free conditions. 7-Hydroxy-2-aryl-6,7-dihydro-indol-4(5H)-ones 3 could also be prepared in moderate yields by the iodine-promoted one pot-two step reactions of methyl ketones 6 with enamines 2. The reaction of 3a with N-methyl indole 7a in the presence of PTSA afforded 2′-aryl-6′,7′-dihydro-[3,7′-biindol]-4′(5′H)-ones 8a in 81% yield. In addition, 3,7′-bis-indoles 8 could also be observed in 47-73% yields by one pot domino reaction of arylglyoxals 1 with enamines 2 and indoles 7 over two steps. This protocol provides a simple and practical method to construct diverse 7-hydroxy-6,7-dihydro-indole derivatives 3 and 3,7′-bis-indoles 8 from easily obtained starting materials.
- Lu, Xin-Mou,Cai, Zhong-Jian,Li, Jian,Wang, Shun-Yi,Ji, Shun-Jun
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p. 51501 - 51507
(2015/06/25)
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- A highly efficient and enantioselective intramolecular cannizzaro reaction under TOX/Cu(II) catalysis
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An asymmetric intramolecular Cannizzaro reaction of aryl and alkyl glyoxals with alcohols has been realized with an unprecedented high level of enantioselectivity, on the basis of a newly developed congested TOX ligand and a gradual liberation protocol of active glyoxals from glyoxal monohydrates. Preliminary results suggested a mechanism of enantioselective addition of alcohols to glyoxals contributing most to the stereoselectivity, other than by the dynamic kinetic resolution of hemiacetal intermediates.
- Wang, Pan,Tao, Wen-Jie,Sun, Xiu-Li,Liao, Saihu,Tang, Yong
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supporting information
p. 16849 - 16852
(2013/12/04)
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