Efficient asymmetric Michael reaction of 2-oxindole-3-carboxylate esters with maleimides catalyzed by cinchonidine
作者:Jing Zhou、Li-Na Jia、Lin Peng、Qi-Lin Wang、Fang Tian、Xiao-Ying Xu、Li-Xin Wang
DOI:10.1016/j.tet.2014.03.065
日期:2014.5
A highly efficient enantioselective Michael reaction of 2-oxindole-3-carboxylate esters with N-maleimides catalyzed by commercially available cinchonidine was described. The desired adducts, containing a quaternary center at the C3-position and a vicinal tertiary center, were obtained in excellent yields (up to 99%), good enantioselectivities (up to 85% ee), and diastereoselectivities (dr>90:10) in the presence of 0.05-5 mol % catalyst loading. (C) 2014 Elsevier Ltd. All rights reserved.