- Copper-catalyzed cyanoisopropylation of beta-keto esters using azos: synthesis of beta-dicarbonyls bearing an alfa-tertiary nitrile moiety
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A copper-catalyzed α-cyanoisopropylation reaction of β-keto esters using azo compounds as cyanoalkylating agents is presented, providing an easy access to β-dicarbonyls containing an α-tertiary nitrile moiety with adjacent tertiary and quaternary carbon centers. It is remarkable because a tremendous steric conflict is involved during reaction. Such nitriles were otherwise unavailable, and the reaction features simple and relatively mild conditions and good functional-group tolerance.
- Li, Yanni,Yang, Ruirong,Zhao, Xiaohui,Yao, Yongchao,Yang, Siping,Wu, Qiong,Liang, Deqiang
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- Electrosynthesis of Dihydropyrano[4,3-b]indoles Based on a Double Oxidative [3+3] Cycloaddition
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Oxidative [3+3] cycloadditions offer an efficient route for six-membered-ring formation. This approach has been realized based on an electrochemical oxidative coupling of indoles/enamines with active methylene compounds followed by tandem 6π-electrocyclization leading to the synthesis of dihydropyrano[4,3-b]indoles and 2,3-dihydrofurans. The radical–radical cross-coupling of the radical species generated by anodic oxidation combined with the cathodic generation of the base from O2 allows for mild reaction conditions for the synthesis of structurally complex heterocycles.
- Choi, Subin,Park, Cheol-Min,Park, Jinhwi,Sim, Jeongwoo,Yu, Eunsoo
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supporting information
p. 11886 - 11891
(2020/05/22)
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- Method of dehydrogenation self-coupling of 1,3-dicarbonyl compound with visible light catalysis
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The invention discloses a method of dehydrogenation self-coupling of a 1,3-dicarbonyl compound with visible light catalysis. The method comprises the following steps of (1) dissolving a photocatalyst,a peroxide and the 1,3-dicarbonyl compound into a solve
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Paragraph 0056; 0057
(2018/09/13)
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- Synthesis and study of the anodic behavior of 1,3,4,6-tetraaryl-2λ4δ2-thieno[3,4-c] thiophenes
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Two heterocyclic compounds based on the thieno[3,4-c]thiophene structure with four aryl substituents were prepared and their behavior in electrooxidation studied. These tetraarylthieno[3,4-c]thiophenes were synthesized in three steps starting from 1,3-dibenzoylmethane in the case of 1,3,4,6-tetraphenyl-2λ4δ2-thieno[3,4-c] thiophene 1a and from 1,3-bis(4′-methoxyphenyl)propane-1,3-dione in the case of 1,3,4,6-tetrakis(4′-methoxyphenyl)-2λ4δ 2-thieno[3,4-c]thiophene 1b, a new compound. Both cyclic and hydrodynamic voltamperometric analyses indicate two reversible one-electron oxidation stages for compound 1b, while for compound 1a only the first stage is reversible. The preparative electrooxidation of the two compounds results in the opening of one thiophene ring giving rise to γ-keto-thioketones.
- Douadi, Tahar,Cariou, Michel
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p. 509 - 520
(2007/10/03)
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- Reaction of Triphenylphosphine Radical Cation with 1,3-Dicarbonyl Compounds: Electrochemical One-Step Preparation of Dioxomethylenetriphenylphosphoranes
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Electrochemical oxidation of Ph3P (1) in MeCN in the presence of 1,3-dicarbonyl compounds, R1COCH2COR2 (3), with HClO4 as the supporting electrolyte resulted in the formation of the phosphonium salts, Ph3P+ -CH(COR1)COR2 ClO4- (4), provided that R1 and/or R2 is a phenyl group.On the other hand, electrolysis in CH2Cl2 with 2,6-lutidinium perchlorate gave the phosphoranes, Ph3P=C(COR1)COR2 (5), directly from 1 and 3 in fair to excellent yields: in this case, R1 or R2 need not necessarily be a phenyl group.Thus, the electrolysis is shown to be a convenient method to prepare 5 in a single step.Plausible processes for the formation of 4 and 5 are proposed, involving the reaction of electrochemically generated Ph3P+. with the enol form of 3 as the keystep.Keywords - triphenylphosphine; 1,3-dicarbonyl compound; dioxomethyltriphenylphosphonium perchlorate; dioxomethylenetriphenylphosphorane; electrochemical oxidation; constant current electrolysis
- Ohmori, Hidenobu,Maeda, Hatsuo,Tamaoka, Mie,Masui, Masaichiro
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p. 613 - 620
(2007/10/02)
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- Selective fluorination by C19XeF6
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Selective fluorination by C19XeF6 of β-diketones and β-ketoesters is described. The ease of handling of this fluorinating reagent and high yields of mono fluorinated products obtained, show promise in organic synthesis.
- Yemul,Kagan,Setton
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p. 277 - 280
(2007/10/02)
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