- An iron(iii)-catalyzed dehydrogenative cross-coupling reaction of indoles with benzylamines to prepare 3-aminoindole derivatives
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We report a green cascade approach to prepare a variety of 3-aminoindole derivatives in good to excellent yields through an iron(iii)-catalyzed dehydrogenative cross-coupling reaction of 2-arylindoles and primary benzylamines under mild reaction conditions. Mechanistic studies show that a cascade reaction involves a tert-butyl nitrite (TBN)-mediated nitrosation of 2-substituted indoles and a 1,5-hydrogen shift to afford indolenine oximes, sequential iron(iii)-catalyzed condensation and a 1,5-hydrogen shift over four steps in a one-pot reaction. The reaction shows a broad substrate scope of indoles and benzylamines and tolerates a wide range of functional groups. Moreover, the reaction is easily performed at the gram scale without producing waste after the reaction is completed. The 3-aminoindole product is purified by simple extraction, washing, and recrystallization without flash column chromatography. A double imine ligand containing the 3-aminoindole unit is facile to obtain in a 52% yield in one step. The present method highlights readily available starting materials, a simple purification procedure, and the usage of cheap, nontoxic, and environmentally benign iron(iii) catalysts. This journal is
- Chen, Wei-Li,Li, Kun,Liang, Cui,Liang, Wang-Fu,Liao, Wei-Cong,Mo, Dong-Liang,Qiu, Pei-Wen,Su, Gui-Fa
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supporting information
p. 9610 - 9616
(2021/12/09)
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- TEMPO-mediated Aza-diels-alder reaction: Synthesis of tetrahydropyridazines using ketohydrazones and olefins
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A novel, facile, and efficient method for the synthesis of tetrahydropyridazines by a one-pot tandem reaction of easily accessible ketohydrazones and olefins in the presence of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) has been successfully developed. The reaction involves the initial generation of azoalkenes from direct oxidative dehydrogenation of ketohydrazones using TEMPO as the commercially available oxidant, followed by a subsequent aza-Diels-Alder reaction with olefins.
- Yang, Xiu-Long,Peng, Xie-Xue,Chen, Fei,Han, Bing
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supporting information
p. 2070 - 2073
(2016/06/09)
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- A mild procedure for the preparation of 3-aryl-4-formylpyrazoles
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A variety of 3-aryl-4-formylpyrazoles can be easily prepared in good yields from the corresponding methyl ketones, upon treatment with 2,4,6-trichloro[1,3, 5]triazine in N,N-dimethyl formamide at room temperature. This kind of pyrazole can constitute new building blocks for combinatorial chemistry.
- De Luca, Lidia,Giacomelli, Giampaolo,Masala, Simonetta,Porcheddu, Andrea
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p. 2299 - 2302
(2007/10/03)
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