Asymmetric Synthesis of Spirooxindoles via Organocascade Strategies

The spirooxindoles have broad and promising activities in various therapeutic areas, and become a privileged skeleton for drug discovery. Therefore, the development of some simple and efficient strategies to build these sophisticated scaffolds has become one of the most widespread concerns. However, the traditional methods are limited by the separation and purification of intermediates, the functional group protection and de-protection. Recently, the cascade strategies have shown special advantages in the synthesis of optically active natural products and complex molecules, many related studies have been reported. This review summarizes the enantioselective synthesis of spirooxindoles via cascade strategies in the past five years and organized on the basis of four types of starting materials: unsaturated oxindole derivatives, C(3)-substituted oxindoles, C(3)-unsubstituted oxindoles and nonoxindoles.