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Article citation: Xin Li, Org. Biomol. Chem., 2010, DOI: 10.1039/b918644a
Asymmetric Michael addition reaction of 3-substituted-N-Boc oxindoles to activated terminal alkenes catalyzed by a bifunctional tertiary-amine thiourea catalyst
Xin Li, Zhi-Guo Xi, Sanzhong Luo and Jin-Pei Cheng
The current article reports an organocatalytic strategy for the asymmetric catalysis of chiral oxindoles bearing 3-position all-carbon quaternary stereocenters. Accordingly, highly enantioselective Michael addition reactions of 3-substituted oxindoles to terminal alkenes have been developed by utilizing a bifunctional tertiary-amine thiourea catalyst. The reactions accommodate a number of Michael donor compounds (different substituted 3-aryl or methyl oxindoles), and Michael acceptor compounds (vinyl ketones and vinyl sulfones) to give the desired oxindole products with moderate to excellent yields (up to 99%) and moderate to excellent enantioselectivities (up to 91% ee).
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