Chiral Counteranion Synergistic Organocatalysis under High Temperature: Efficient Construction of Optically Pure Spiro[cyclohexanone-oxindole] Backbone

The combination of a cinchona-based chiral primary amine and a BINOL-phosphoric acid has been demonstrated as a powerful and synergistic catalyst system for the double Michael addition of isatylidene malononitriles with alpha,beta-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 dr's, 95-99% ee's).