Organocatalytic asymmetric conjugate addition of cyclic 1,3-dicarbonyl compounds to β,γ-unsaturated α-ketoesters
作者:Jin-jia Wang、Jin-hua Lao、Zhi-peng Hu、Rui-Jiong Lu、Shao-zhen Nie、Quan-sheng Du、Ming Yan
DOI:10.3998/ark.5550190.0011.922
日期:——
The conjugateaddition of cyclic1,3-dicarbonylcompounds to β,γ-unsaturated α-keto-esters was studied using a series of chiral bifunctional organocatalysts. Takemoto’s catalyst was found to be most efficient for this transformation. Excellent yields and good enantioselectivities were achieved for a variety of β,γ-unsaturated α-keto-esters and cyclic1,3-dicarbonylcompounds. A bifunctional catalytic
Conjugate Addition of Carbon Acids to β,γ-Unsaturated α-Keto Esters: Product Tautomerism and Applications for Asymmetric Synthesis of Benzo[<i>a</i>]phenazin-5-ol Derivatives
作者:Rinat S. Tukhvatshin、Alexander S. Kucherenko、Yulia V. Nelyubina、Sergei G. Zlotin
DOI:10.1021/acs.joc.9b02021
日期:2019.11.1
by the asymmetric Michael reactions of cyclic carbon acids with β,γ-unsaturated α-keto esters and the chemical shift of the α-proton in starting nucleophilic substrates was revealed which makes equilibration predictable. New tetrahydropyran-fused benzo[a]phenazins were enantioselectively (up to 99% ee) synthesized from β,γ-unsaturated α-keto esters and benzo[a]phenazin-5-ol, a powerful anti-cancer agent
Azetidine-Derived Dinuclear Zinc-Catalyzed Asymmetric Conjugate Addition of Bioactive Heterocycles to β,γ-Unsaturated α-Keto esters
作者:Shanshan Liu、Zhi-Hua Xu、Xi Wang、Hao-Ran Zhu、Min-Can Wang
DOI:10.1021/acs.joc.9b02046
日期:2019.11.1
A general AzePhenol dinuclear zinc catalytic system has been successfully developed and applied into the asymmetric Michaeladdition of 4-hydroxyl pyrones and 4-hydroxycoumarins to β,γ-unsaturated α-keto esters. Excellent yields (up to 99%) and high enantioselectivities (up to 94% ee) are obtained for a wide range of substrates under mild conditions in the absence of additives. This bimetallic catalytic
4-hydroxycoumarin to β,γ-unsaturated α-ketoesters. The catalyst system performed well with a low catalyst loading of 1 mol% under mild reaction conditions. A series of coumarinderivatives were obtained with good yields and enantioselectivities