phase‐transfer reaction system can be applied to highly enantioselectiveconjugateaddition and aldol reactions under the influence of chiral bifunctional ammonium bromides as key catalysts. The structure of the chiral ammonium enolate intermediate is discussed based on the single‐crystal X‐ray structures of relevant ammonium salts and the importance of bifunctional design of catalyst is clearly explained in the
Chiral Phosphine Catalyzed Asymmetric Michael Addition of Oxindoles
作者:Fangrui Zhong、Xiaowei Dou、Xiaoyu Han、Weijun Yao、Qiang Zhu、Yuezhong Meng、Yixin Lu
DOI:10.1002/anie.201208285
日期:2013.1.14
Bifunctional phosphines derived from amino acids mediate the asymmetric Michaeladdition of 3‐substituted oxindoles to activated alkenes (see scheme). Biologically relevant chiral 3,3‐disubstitutedoxindoles were thus prepared in high yields and with excellent enantioselectivities from 3‐aryl‐ and 3‐alkyl‐substituted oxindoles and various activated alkenes.