highly diastereo- and enantioselective aerobic oxidation–Michael–carbocyclization cascadetransformations by integrated heterogeneous Pd(0)-CPG nanoparticle/chiral amine relay catalysis are disclosed. The heterogeneous Pd(0)-CPG nanoparticle catalysts were efficient for both the sequential aerobic oxidation and dynamic kinetic asymmetric Michael–carbocyclization transformations, resulting in 1) oxidation
Enantioselective Heterogeneous Synergistic Catalysis for Asymmetric Cascade Transformations
作者:Luca Deiana、Lorenza Ghisu、Samson Afewerki、Oscar Verho、Eric V. Johnston、Niklas Hedin、Zoltan Bacsik、Armando Córdova
DOI:10.1002/adsc.201400291
日期:2014.8.11
AbstractA modular design for a novel heterogeneous synergistic catalytic system, which simultaneously activates the electrophile and nucleophile by the combined activation modes of a separate metal and non‐metal catalyst, for asymmetric cascade transformations on a solid surface is disclosed. This modular catalysis strategy generates carbocycles (up to 97.5:2.5 er) as well as spirocyclic oxindoles (97.5:2.5 to >99:0.5 er), containing all‐carbon quaternary centers, in a highly enantioselective fashion via a one‐pot dynamic relay process.magnified image
The Use of Porous Palladium(II)-polyimine in Cooperatively- catalyzed Highly Enantioselective Cascade Transformations
porous palladium(II)‐polyimines are excellent catalysts for cooperatively catalyzed and enantioselective cascadereactions. In synergy with a chiral amine co‐catalyst, polysubstituted cyclopentenes and spirocyclic oxindoles, including the all‐carbon quaternary stereocenter, were synthesized in high yields. High diastereo‐ and enantioselectivities were achieved for these dynamic kinetic asymmetric transformations
The first examples of one‐pot highly chemo‐ and enantioselectivedynamickineticasymmetrictransformations (DYKATs) involving α,β‐unsaturated aldehydes and propargylated carbon acids are presented. These DYKATs, which proceed by a combination of catalytic iminium activation, enamine activation, and Pd0‐catalyzed enyne cycloisomerization, give access to functionalized cyclopentenes with up to 99 % ee