Isopropylmagnesium chloride-promoted unilateral addition of Grignard reagents to β-diketones: one-pot syntheses of β-tertiary hydroxyl ketones or 3-substituted cyclic-2-enones
作者:Rui Yuan、Dan Zhao、Li-Yuan Zhang、Xiang Pan、Yan Yang、Pei Wang、Hong-Feng Li、Chao-Shan Da
DOI:10.1039/c5ob02072g
日期:——
unilateral additions of Grignardreagents to acyclic or cyclic β-diketones were effectively promoted by sub-stoichiometric amounts of i-PrMgCl to afford β-tertiary hydroxyl ketones or 3-substituted cyclic-2-enones, respectively. Also, the addition of Grignardreagents to acyclic β-diketones followed by a reaction with cyclic β-diketones in a one-pot process was put forward. The reaction mechanism was discussed
A lithium-bromide-promoted nucleophilicsubstitution/annulation cascade reaction between CF3-imidoyl sulfoxonium ylides and 1,3-dicarbonyl compounds has been established, and the corresponding 1,2,3-trisubstituted 5-trifluoromethylpyrroles have been obtained in 27–78% yield. This reaction features a broad substrate scope and generates dimethylsulfoxide and H2O as byproducts.
已经建立了溴化锂促进的 CF 3 -亚氨酰基锍叶立德与 1,3-二羰基化合物之间的亲核取代/环化级联反应,并在 27-78 年获得了相应的 1,2,3-三取代 5-三氟甲基吡咯% 屈服。该反应具有广泛的底物范围,并生成二甲基亚砜和 H 2 O 作为副产物。
A formal [3 + 3] cycloaddition of allenyl imide and activated ketones for the synthesis of tetrasubstituted 2-pyrones
CsOH·H2O-catalyzed formal [3 + 3] cycloadditions of allenyl imide with β-ketoesters, 1,3-diketones or β-ketonitriles for the synthesis of tetrasubstituted 2-pyrone derivatives have been demonstrated. The allenyl imide was utilized as a C3-synthon, and a ketenyl intermediate was proposed via the process of 1,4-addition of carbon anion to allene followed by elimination of the 2-oxazolidinyl group.
Organocatalytic asymmetric Michael/hemiketalization/acyl transfer reaction of 1,3-propanediones with (<i>E</i>)-2-(2-nitrovinyl)phenols
作者:Nimisha Bania、Subhas Chandra Pan
DOI:10.1039/c8ob01771a
日期:——
An organocatalyticasymmetriccascadeMichael/hemiketalization/acyl transfer reaction between (E)-2-(2-nitrovinyl)phenols and 1,3-propanediones is disclosed. A cinchona alkaloid derived bifunctional thiourea catalyst was found to be the most effective for this reaction and provided the desired products in moderate to good yields with good to high enantioselectivities.
Gold-Catalyzed Formal C−C Bond Insertion Reaction of 2-Aryl-2-diazoesters with 1,3-Diketones
作者:Yuan-Yuan Ren、Mo Chen、Ke Li、Shou-Fei Zhu
DOI:10.1002/asia.201800934
日期:2018.9.17
Brønsted acid to the reaction mixture improves the yield of the C−C bond insertion product. A reaction mechanism involving cyclopropanation of a gold carbenoid with an enolate and ring‐opening of the resulting donor–acceptor‐type cyclopropane intermediate is proposed. This mechanism differs from that of the traditional Lewis‐acid‐catalyzed C−C bond insertionreaction of diazo compounds with monocarbonyl