Asymmetric organocatalytic conjugate addition of dialkyl phosphites to N-unprotected isatylidene malononitriles: access to 3-phospho-2-oxindoles with chiral quaternary stereocenters
作者:Zhao-Min Liu、Nai-Kai Li、Xiao-Fei Huang、Bing Wu、Ning Li、Chun-Yuen Kwok、Yong Wang、Xing-Wang Wang
DOI:10.1016/j.tet.2014.02.023
日期:2014.4
established for the first time by using a simple bifunctional tertiary amine–thioureacatalyst. The corresponding adducts, 3-phospho-2-oxindoles, containing a chiral quaternary carbon center at the 3-position of the oxindole, were obtained in good to excellent yields (up to 98%) with moderate to excellent enantioselectivities (up to 95% ee). In addition, optically active 3,3′-disubstituted oxindoles bearing carboxylate