- Regioselective hydrations of 1-aryl-3-en-1-ynes using gold and platinum catalysts: Selective production of 2-en-1-ones and 3-en-1-ones
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Regiocontrolled hydrations of 1-aryl-3-en-1-ynes have been accomplished with IPrAuOTf and PtCl2/CO to yield 3-en-1-ones and 2-en-1-ones efficiently; our experimental data indicates that the sizes of catalysts play an important role. This journa
- Mokar, Bhanudas Dattatray,Liu, Rai-Shung
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supporting information
p. 8966 - 8969
(2014/08/05)
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- A stereoselective and practical synthesis of (E)-α,β-unsaturated ketones from aldehydes
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α,β-Unsaturated ketones can be prepared by reaction of differently substituted β-keto acids and aldehydes. The reaction is carried out under organocatalysis (β-alanine, 0.5 equiv.) and generates the enones with high E selectivity (>95%). This version of the Verley-Doebner modification of the Knoevenagel reaction is a practical alternative to the classic Horner-Wadsworth-Emmons (HWE) reaction without the formation of high molecular weight byproducts. The process makes use of simple reagents and can be applied to large-scale synthesis under conditions compatible with atom-economy principles. Differently substituted aliphatic, aromatic, or heteroaromatic α,β-unsaturated ketones can be prepared. An example of a hydroformylation/Verley-Doebner Knoevenagel telescoped process is also described. The conditions used in the Knoevenagel reaction to prepare conjugated esters under amino acid organocatalysis can be applied also for the synthesis of α,β unsaturatedketones. β-Keto acids are prepared byhydrogenolysis of the corresponding benzyl ester and react easily with aldehydes to give the α,β-unsaturated ketones without formation of high molecular weight byproducts. Copyright
- Balducci, Evita,Attolino, Emanuele,Taddei, Maurizio
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experimental part
p. 311 - 318
(2011/02/28)
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- Benzotriazole- and 1,2,4-triazole-stabilized allylic anions: Applications in syntheses of functionalized α,β-unsaturated ketones, γ-lactones, γ-lactams, and β-substituted esters
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Deprotonated 1-(benzotriazol-1-yl)-1-ethoxy-2-hexene (7) reacted with alkyl halides, aldehydes, ketones, imines, and α,β-unsaturated esters to give exclusively the α-alkylated products 8a-c, 10a,b, 12, 14, 16, and 18a,b, respectively. Without isolation, these products were hydrolyzed under mild conditions to generate the corresponding simple or functionalized α,β-unsaturated ketenes 9a-c, 11a,b, 13, 15, 17, and 19a,b. Similar reactions with the phenyl-substituted analog 3-(benzotriazol-1-yl)-3-ethoxy-1-phenyl-1-propene (21) also gave the analogous α-products, but they were accompanied by small amounts of the γ-products in most cases. By contrast, deprotonation of the corresponding triazole derivative 29 with butyllithium followed by reactions with alkyl halides, aldehydes, ketones, or imines yielded exclusively γ-alkylated adducts 32, 34, 36, 38, 40, and 42. Intermediates 32, 34, 36, 38, 40, and 42 were readily converted into β-substituted esters 33a-c, γ-lactones 35a,b, 39, 41, and 43, and γ-lactams 37a-c on hydrolysis.
- Katritzky,Feng,Lang
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p. 706 - 714
(2007/10/03)
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- A new synthesis of α-β-unsaturated ketones
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α,β-unsaturated ketones have been obtained by thermolysis of δ-hydroxy β-keto triphenylphosphoranes prepared from the corresponding β-keto phosphoranes.
- Le Roux,Le Corre
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p. 2591 - 2594
(2007/10/02)
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