82297-67-4Relevant academic research and scientific papers
A stereoselective and practical synthesis of (E)-α,β-unsaturated ketones from aldehydes
Balducci, Evita,Attolino, Emanuele,Taddei, Maurizio
experimental part, p. 311 - 318 (2011/02/28)
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
Palladium-catalysed heck reactions of alk-1-en-3-ones with aryl bromides: A very simple access to (E)-1-arylalk-1-en-3-ones
Lemhadri, Mhamed,Fall, Yacoub,Doucet, Henri,Santelli, Maurice
experimental part, p. 1021 - 1035 (2009/12/02)
When appropriate reaction conditions are used, very high yields of (E)-1-arylalk-1-en-3-one derivatives can be obtained by palladium-catalysed reactions of alk-1-en-3-ones with aryl bromides. The tetraphosphine cis,cis,cis-1,2,3,4-tetrakis(diphenylphosphinomethyl) cyclopentane in combination with [Pd(C3H5)Cl]2 was found to be a very efficient catalyst for this reaction. In general, higher reaction rates were observed with electron-poor aryl bromides, but the electron-rich aryl bromides 1-bromo-4-(dimethylamino)benzene and 4-bromoanisole also led to the arylated enones in high yields. Even with sterically very congested aryl bromides such as 9-bromoanthracene, 1-bromo-2,4,6-trimethylbenzene or 1-bromo-2,4,6-triisopropylbenzene, the expected (E)-1-arylalk-1-en-3-ones were obtained in moderate to good yields. These enones appear to be unstable under the reaction conditions, and the addition of a small amount of hydroquinone to the reaction mixture was found to be crucial, especially for the vinylation of electron-deficient aryl bromides. A variety of alk-1-en-3-ones has been employed, and better results in terms of substrate/ catalyst ratios were obtained when oct-1-en-3-one or hex-1-en-3-one was used than when but-1-en-3-one or pent-1-en-3-one was used. It should be noted that several reactions can be performed with as little as 0.1-0.001 mol% catalyst. Georg Thieme Verlag Stuttgart.
One single catalyst, Pd(OAc)2, for two sequential very different steps: Allylic alcohol oxidation-Heck reaction. Access to functionalised α,β-unsaturated ketones
Batt, Frederic,Gozzi, Christel,Fache, Fabienne
supporting information; experimental part, p. 5830 - 5832 (2009/04/13)
A single addition of the catalyst, Pd(OAc)2, was realised to mediate two transformations as different as allylic alcohol oxidation under O2 and C-C bond formation of the Heck type, to give substituted α,β-unsaturated ketones without intermediate purification. The Royal Society of Chemistry.
Gallium(III) chloride catalyzed stereoselective synthesis of E-configured α,β-unsaturated ketones
Yadav,Reddy, B. V. Subba,Gupta, Manoj K.,Dash, Uttam,Pandey, Sushil K.
, p. 809 - 811 (2007/12/26)
A simple and highly stereoselective method has been developed for the synthesis of E-configured α,β-unsaturated ketones using gallium(III) chloride as a novel catalyst. This new procedure offers significant advantages such as high conversions, short reac-tion times and enhanced E-selectivity together with mild reaction conditions. Georg Thieme Verlag Stuttgart.
N,O-HETEROCYCLICS-14 CONVERSION OF ISOXAZOLIDINES INTO α,β-ENONES
Liguori, Angelo,Sindona, Giovanni,Uccela, Nicola
, p. 1901 - 1906 (2007/10/02)
Substituted isoxazolidines formed by 1,3-dipolar cycloaddition of nitrones to alkenes undergo ring-opening elimination to α,β-enones when treated with trimethyl phosphate.The reaction involves initial alkylation giving the isoxazolidinium intermediate which collapses to the α,β-enone by a Hofmann-like elimination having an orientation controlled by electronic factors, the first step being rate-determining.
