Asymmetric Direct Vinylogous Michael Reaction Catalyzed by Self-Assembled Organocatalyst
作者:Wei-Yi Chen、Luo Ouyang、Rui-Ye Chen、Xin-Sheng Li
DOI:10.1080/00397911.2011.563023
日期:2012.9
Abstract The self-assembled organocatalyst of cinchonaalkaloidderivatives and amino acids has been applied to a direct asymmetric vinylogous Michael addition of α,α-dicyanoolefins to nitroolefins; the corresponding products could be obtained in moderate to good yields and enantioselectivities. GRAPHICAL ABSTRACT
chiral thiourea-tertiary amine organocatalysts have been applied to a direct asymmetric vinylogousMichaeladdition of α,α-dicyanoolefins to nitroolefins with 2–10 mol % catalyst loadings. The electronic properties of the thiourea-based catalysts have significant influences on this reaction. Moderate to excellent enantioselectivities (57–95% ee) have been achieved with low to good isolated yields through
Organocatalytic asymmetric allylic carbon–carbon bond formation
作者:Thomas B. Poulsen、Mark Bell、Karl Anker Jørgensen
DOI:10.1039/b514564c
日期:——
bond-forming addition of activated alkylidenes to alkyl and aryl nitroalkenes has been achieved with high diastereo- and enantioselectivity. Chiral tertiary amine catalysts are used to give allyl intermediates which exhibit gamma-selectivity in the C-C bond forming step. The reactions proceed with up to >99:1 syn:anti ratio for both the alkyl- and aryl nitroalkenes with up 96% and 98% ee, respectively
Asymmetric Direct Vinylogous Michael Reaction of Activated Alkenes to Nitroolefins Catalyzed by Modified Cinchona Alkaloids
作者:Dong Xue、Ying-Chun Chen、Qi-Wei Wang、Ling-Feng Cun、Jin Zhu、Jin-Gen Deng
DOI:10.1021/ol052283b
日期:2005.11.1
[reaction: see text] The first organocatalytic and asymmetric directvinylogousMichael reaction that employs the electron-deficient vinyl malononitriles as the nucleophilic species has been reported. The novel transformations exhibit exclusive gamma-selectivity and high diastereo- and enantioselectivity in the addition to nitroolefins, which give the multifunctional products with two vicinal chiral