5452-52-8Relevant academic research and scientific papers
Selective catalytic synthesis of α-alkylated ketones and β-disubstituted ketones via acceptorless dehydrogenative cross-coupling of alcohols
Bhattacharyya, Dipanjan,Sarmah, Bikash Kumar,Nandi, Sekhar,Srivastava, Hemant Kumar,Das, Animesh
supporting information, p. 869 - 875 (2021/02/06)
Herein, a phosphine-free pincer ruthenium(III) catalyzed β-alkylation of secondary alcohols with primary alcohols to α-alkylated ketones and two different secondary alcohols to β-branched ketones are reported. Notably, this transformation is environmentally benign and atom efficient with H2O and H2 gas as the only byproducts. The protocol is extended to gram-scale reaction and for functionalization of complex vitamin E and cholesterol derivatives.
Asymmetric transfer hydrogenation of unsaturated ketones; factors influencing 1,4- vs 1,2- regio- and enantioselectivity, and alkene vs alkyne directing effects
Hall, Thomas H.,Adams, Hannah,Vyas, Vijyesh K.,Michael Chu,Wills, Martin
, (2020/12/07)
A detailed study has been completed on the asymmetric transfer hydrogenation (ATH) of a series of enones using Ru(II) catalysts. Electron-rich rings adjacent to the C[dbnd]O group reduce the level of C[dbnd]O reduction compared to C[dbnd]C. The ATH reaction can readily discriminate between double and triple bonds adjacent to ketones, reducing the double bond but leaving a triple bond intact in the major product.
Acylation of Alkenes with the Aid of AlCl3 and 2,6-Dibromopyridine
Tanaka, Shinya,Kunisawa, Tsukasa,Yoshii, Yuji,Hattori, Tetsutaro
supporting information, p. 8509 - 8513 (2019/11/03)
Friedel-Crafts-type acylation of alkenes with acyl chlorides has been successfully conducted with a wide substrate scope by the combined use of AlCl3 and 2,6-dibromopyridine. Trisubstituted alkenes afford allylketones or vinylketones depending on the presence or absence of hydrogen atom(s) at the β-position to the acylation site, while monosubstituted alkenes exclusively afford vinylketones.
Triazole-gold-promoted, effective synthesis of enones from propargylic esters and alcohols: A catalyst offering chemoselectivity, acidity and ligand economy
Wang, Dawei,Zhang, Yanwei,Harris, Alexandria,Gautam, Lekh Nath S.,Chen, Yunfeng,Shi, Xiaodong
supporting information; experimental part, p. 2584 - 2588 (2011/12/01)
The air, moisture and thermally stable 1,2,3-triazole coordinated gold(I) complexes (TA-Au) were revealed as the effective catalysts in promoting propargylic ester rearrangement and sequential allene hydration, giving the enones with excellent yields (up to 97% yields, 0.2% loading). The catalysts could also catalyze the more challenging Meyer-Schuster rearrangement (0.5% loading, up to 98% yields). The reported reaction confirmed TA-Au as a chemoselective catalyst in promoting alkyne activation with high efficiency and improved ligand economy. Copyright
Gold-catalyzed highly regioselective oxidation of C-C triple bonds without acid additives: Propargyl moieties as masked α,β-unsaturated carbonyls
Lu, Biao,Li, Chaoqun,Zhang, Liming
supporting information; experimental part, p. 14070 - 14072 (2011/01/04)
Gold-catalyzed intermolecular oxidations of internal alkynes have been achieved with high regioselectivities using 8-alkylquinoline N-oxides as oxidants and in the absence of acid additives. Synthetically versatile α,β-unsaturated carbonyls are obtained in good to excellent yields and with excellent E-selectivities. A range of functional groups such as THP, MOMO, N3, OTBS, and N-Boc are tolerated. This reaction allows α,β-unsaturated carbonyls to be masked as propargyl moieties, thus offering a practical solution to compatibility issues with these functional groups likely encountered in syntheses of complex structures.
Gold-catalyzed efficient formation of α,β-unsaturated ketones from propargylic acetates
Yu, Meng,Li, Guotao,Wang, Shaozhong,Zhang, Liming
, p. 871 - 875 (2008/03/27)
An efficient gold-catalyzed method for the preparation of α,β-unsaturated ketones from propargylic acetates has been developed. Under mild reaction conditions, β-monosubstituted enones were formed mostly with excellent E-selectivity. β,β-Disubstituted enones can be prepared from propargylic acetates derived from ketones. The high efficiency and mild nature of this reaction render it a viable alternative for the synthesis of α,β-unsaturated ketones.
Multicomponent synthesis of dihydropyrimidines and thiazines
Vugts, Danielle J.,Koningstein, Manoe M.,Schmitz, Rob F.,De Kanter, Frans J. J.,Groen, Marinus B.,Orru, Romano V. A.
, p. 7178 - 7189 (2007/10/03)
A broad range of differently substituted dihydropyrimidines and thiazines can be efficiently prepared by using a four-component reaction between phosphonates, nitriles, aldehydes, and iso(thio)cyanates. The scope and limitations of this multicomponent reaction are fully described. Variation of all four components has been investigated. The nitrile and aldehyde inputs can be varied extensively, but variation of the phosphonate input remains limited. An interesting rearrangement leading to phosphoramidates has been observed, Furthermore, the multicomponent reaction seems to be restricted to the use of isocyanates with strongly electron-withdrawing substituents, but an interesting additional exchange reaction under microwave conditions leads to dihydropyrimidines with less electron-withdrawing substituents at N3. In addition, a diastereoselective formation of dihydropyrimidines has been observed when using a chiral aldehyde as the input. Finally, by changing the isocyanate component to an isothiocyanate, thiazines are efficiently formed instead of the corresponding thio-dihydropyrimidines.
Oxidative Generation of 1-Nitroalkyl Radicals and Their Addition Reaction to Olefins
Arai, Noriyoshi,Narasaka, Koichi
, p. 2525 - 2534 (2007/10/03)
1-Nitroalkyl radicals are generated by oxidation of potassium salt of 1-aci-nitroalkanes with ammonium hexanitratocerate(IV). When the oxidation is carried out in the presence of electron-rich olefins, such as silyl enol ethers, intermolecular addition of the radicals onto the olefins proceeds to afford β-nitro ketones, which are further converted to α,β-unsaturated ketones in high yield. Stereoselective construction of fused ring systems is achieved by intramolecular addition of 1-nitroalkyl radicals.
Generation of α-Nitroalkyl Radicals by Oxidation of Nitronate Anions with Cerium(IV) Ammonium Nitrate and Their Addition Reaction to Electron-Rich Olefins
Arai, Noriyoshi,Narasaka, Koichi
, p. 987 - 988 (2007/10/03)
α-Nitroalkyl radicals are generated by oxidation of nitronate anions with cerium(IV) ammonium nitrate.When the reactions are carried out in hte presence of electron-rich olefins, such as silyl enol ethers, intermolecular addition of the radicals proceeds to afford β-nitroketones, which are further converted to α,β-unsaturated ketones in good yield.
On tertiary stibine I. Reaction of ω-bromoacetophenone with aldehydes mediated by diphenylantimonyorganometallic reagents
Zhang, Li-Jun,Huang, Yao-Zeng
, p. 101 - 103 (2007/10/02)
In the presence of diphenylantimonymagnesium, various aldehydes react readily with ω-bromoacetophenone to form α,β-unsaturated ketones in good yields.
