Abstract
Highly efficient diastereo- and enantioselective Michael addition reactions between 3-substituted oxindoles and trifluoromethylated nitro olefins catalyzed by a quinine-derived squaramide have been investigated. The corresponding adducts, each bearing a chiral tertiary carbon center attached to a trifluoromethyl group and adjacent to a quaternary stereocenter at the C3 position of the oxindole, were obtained in good to excellent yields (up to 99 %) and with high diastereoselectivities (up to >20:1 dr) and excellent enantioselectivities (up to 99 % ee).