Chiral Counteranion Synergistic Organocatalysis under High Temperature: Efficient Construction of Optically Pure Spiro[cyclohexanone-oxindole] Backbone
作者:Yu-Bao Lan、Hua Zhao、Zhao-Min Liu、Guo-Gui Liu、Jing-Chao Tao、Xing-Wang Wang
DOI:10.1021/ol201943g
日期:2011.9.16
The combination of a cinchona-based chiral primary amine and a BINOL-phosphoric acid has been demonstrated as a powerful and synergistic catalystsystem for the double Michaeladdition of isatylidene malononitriles with α,β-unsaturated ketones, to provide the novel chiral spiro [cyclohexane-1,3′-indoline]-2′,3-diones in high yields (88–99%) with excellent diastereo- and enantioselectivities (94:6–99:1