22391-01-1Relevant articles and documents
Visible-Light-Promoted Synthesis of α-CF2H-Substituted Ketones by Radical Difluoromethylation of Enol Acetates
Cheng, Li,Dong, Bingbing,Feng, Zengqiang,Li, Yunpu,Wang, Zechao,Wu, Junliang,Zhu, Baoxiang
supporting information, p. 508 - 513 (2021/01/13)
An efficient and novel visible-light-promoted radical difluoromethylation of enol acetates for the synthesis of α-CF2H-substituted ketones has been described. Upon irradiation under blue LED with catalytic amounts of fac-Ir(ppy)3, this photocatalytic procedure employs difluoromethyltriphenylphosphonium bromide as a radical precursor. Various α-CF2H-substituted ketones are successfully created via designed systems based on the SET process. The methodology has also provided an operationally simple process with broad functional group compatibility.
Ag2CO3-mediated direct functionalization of alkyl nitriles: Facile synthesis of γ-ketonitriles through nitrile alkylation of enol acetates
Cheng, Pi,Wang, Wei,Wang, Lin,Zeng, Jianguo,Reiser, Oliver,Liang, Yun
, p. 1408 - 1412 (2019/05/06)
Direct C(sp3)-H functionalization of alkyl nitriles is a low toxic and facile route to nitrile-containing compounds. In this research, the Ag2CO3-mediated nitrile methylenation of enol acetates is developed to prepare γ-ketonitriles through the direct C(sp3)-H oxidative functionalization of acetonitrile. A radical pathway is proposed, and acetonitrile serves both as solvent and CN-containing radical source.
Synthesis of 1,4-Diketones from β-Oxo Esters and Enol Acetates by Cerium-Catalyzed Oxidative Umpolung Reaction
Geibel, Irina,Christoffers, Jens
supporting information, p. 918 - 920 (2016/03/01)
Cyclic β-oxo esters are converted with enol acetates in a cerium-catalyzed, oxidative Umpolung reaction to furnish 1,4-diketones with up to 95 % yield. Atmospheric oxygen is the oxidant in this process, which can be regarded as ideal from economic and ecological points of view. Further advantages of this new C-C coupling reaction are its operational simplicity and the application of nontoxic and inexpensive CeCl3·7H2O as precatalyst.
Highly efficient Cu(I)-catalyzed trifluoromethylation of aryl(heteroaryl) enol acetates with CF3 radicals derived from CF3SO 2Na and TBHP at room temperature
Lu, Yang,Li, Yaming,Zhang, Rong,Jin, Kun,Duan, Chunying
, p. 128 - 133 (2014/05/06)
An efficient method for the Cu(I)-catalyzed synthesis of α-trifluoromethyl ketones via the addition of CF3 to aryl(heteroaryl) enol acetates by using the readily available CF 3SO2Na (Langlois reagent) has been developed. The reaction is experimentally simple and carried out at room temperature, providing good to excellent yields with wide functional group tolerance.
Modular P-OP ligands in rhodium-mediated asymmetric hydrogenation: A comparative catalysis study
Nunez-Rico, Jose L.,Etayo, Pablo,Fernandez-Perez, Hector,Vidal-Ferran, Anton
supporting information, p. 3025 - 3035 (2013/01/15)
Highly efficient and enantioselective hydrogenation reactions for α-(acylamino)acrylates, itaconic acid derivatives and analogues, α-substituted enol ester derivatives, and α-arylenamides (25 substrates) catalyzed by chiral cationic rhodium complexes of a set of P-OP ligands have been developed. The catalytic systems derived from these P-OP ligands provided a straightforward access to enantiomerically enriched α-amino acid, carboxylic acid, amine, and alcohol derivatives that are valuable chiral building blocks. Excellent efficiencies (full conversion in all cases) and extremely high enantiomeric excesses (94-99% ee) were achieved for a wide range of α-substituted enol ester derivatives, regardless of the substitution pattern. The R-oxy group of the ligand (methoxy or triphenylmethoxy) strongly influences the enantioselectivity and catalytic activity. Greater steric bulk around the metal centre correlated to greater (or similar) enantioselectivity, but also to slower hydrogenation. Furthermore, the hydrogenation rates observed with the four model substrates follow the same trend, independently of the R-oxy group of the ligand: methyl 2-acetamidoacrylate>dimethyl itaconate>1-phenylvinyl acetate>N-(1- phenylvinyl)acetamide. A substrate-to-catalyst ratio (S/C) of up to 10,000:1 was sufficient for total hydrogenation of a model substrate of intermediate reactivity (dimethyl itaconate), and did not imply any loss in conversion or enantioselectivity. Copyright
