Asymmetric Synthesis of Multicyclic Spirooxindole Derivatives Bearing Stereogenic Quaternary Carbon Atoms.

An organocatalyzed stereoselective domino reaction as a facile approach to multicyclic spirooxindole derivatives bearing two stereogenic quaternary carbon atoms is reported. The alkyl-substituted chiral thiourea catalyst was efficient for the reaction to tolerate a wide range of substrates, furnishing a new class of spirooxindole derivatives bearing an O , O -acetal-fused tricyclic skeleton or tetrahydroxanthone moiety in moderate to good yields with good to excellent selectivities. The products generated from this method have promising anticancer activities.