generated hydroxy‐o‐quinodimethanes with high stereoselectivity. We used a chiral organic catalyst, derived from natural cinchona alkaloids, to activate maleimides toward highly stereoselective Diels–Alder reactions. An unconventional mechanism of stereocontrol is operative, wherein the organocatalyst is actively involved in both the photochemical pathway, by leveraging the formation of the reactive photoenol
Asymmetric organocatalytic anthrone additions to activated alkenes
作者:Alex Zea、Andrea-Nekane R. Alba、Natalia Bravo、Albert Moyano、Ramon Rios
DOI:10.1016/j.tet.2011.02.032
日期:2011.4
Asymmetric organocatalyticadditions of anthrones to activated alkenes are discussed. The reaction between anthrone or dithranol and α,β-unsaturated aldehydes is catalyzed by diphenylprolinol trimethylsilyl ether in toluene at −40 °C, giving the Michael adducts with good yields and enantioselectivities. Bifunctional amino-thioureas efficiently catalyze the additions of anthrones to both nitroalkenes and maleimides
One-Pot Tandem Diastereoselective and Enantioselective Synthesis of Functionalized Oxindole-Fused Spiropyrazolidine Frameworks
作者:Liang-Yong Mei、Xiang-Ying Tang、Min Shi
DOI:10.1002/chem.201403990
日期:2014.10.6
A highly efficient palladium(0)‐catalyzed asymmetric [3+2] cycloaddition using 3‐diazooxindoles serving as dipolarophiles affords functionalized pyrazolidinederivatives in an atom‐economical way. In addition, by trapping the pyrazolidinederivatives with maleimides, the corresponding spiropyrazolidine oxindoles containing multiple stereogenic centers have been obtained in high yields along with moderate
Enantioselective Intermolecular Rauhut-Currier Reaction of Electron-Deficient Allenes with Maleimides
作者:Qian-Yi Zhao、Cheng-Kui Pei、Xiao-Yang Guan、Min Shi
DOI:10.1002/adsc.201100434
日期:2011.8
4-diazabicyclic[2.2.2]octane (DABCO)-catalyzed intermolecularRauhut–Currierreaction of maleimides with electron-deficientallenes has been investigated, affording the corresponding products in good to high yields under mild conditions. The first example of a β-isocupreidine (β-ICD)-catalyzed highly enantioselectiveintermolecularRauhut–Currierreaction of maleimides with allenoates and penta-3,4-dien-2-one
The enantioselective synthesis of pyrazol-3-ones has not been extensively studied in organic synthesis. Here in we report the first asymmetric addition of pyrazolones to maleimides catalyzed by bifunctional thiourea catalysts.