Bifunctional Quaternary Ammonium Salts Catalyzed Stereoselective Conjugate Addition of Oxindoles to Electron-Deficient β-Haloalkenes
作者:Qiaowen Jin、Changwu Zheng、Gang Zhao、Gang Zou
DOI:10.1021/acs.joc.7b00571
日期:2017.5.5
A highly Z-selective asymmetric conjugate addition of 3-substitutedoxindoles to β-haloalkene ketones/esters catalyzed by readily available chiral bifunctional quaternary ammonium salts is reported. This reaction provides efficient access to a range of 2-oxoindole derivatives bearing a thermodynamically unstable Z-olefin structure and a chiral quaternary carbon center in high yields (up to 90%) and
Asymmetric Michael Addition of Oxindoles to Allenoate Catalyzed by<i>N</i>-Acyl Aminophosphine: Construction of Functionalized Oxindoles with Quaternary Stereogenic Center
作者:Jinhao Chen、Yuepeng Cai、Gang Zhao
DOI:10.1002/adsc.201300695
日期:2014.2.10
AbstractA novel reaction between ethyl allenoate and oxindoles that enables the asymmetric synthesis of 3,3‐bisubstituted oxindoles with our previously established bifunctional N‐acyl aminophosphine catalysts is reported. These products bearing a chiral quaternary carbon center at the C‐3 position of the oxindoles may have potential significance in the synthesis of related structures. The best performance of these processes provides adducts with 92% yield and 94% ee.magnified image