Synthesis and Diversification of Chiral Spirooxindoles via Organocatalytic Cascade Reactions

Abstract

The synthesis of chiral spirooxindoles through different amino catalytic activation modes is described herein. Several alkenylisatins were obtained from the Knoevenagel reaction of isatin and activated methylene derivatives containing electron withdrawing groups such as ethyl cyanoacetate. A spirooxindole derivative was obtained from the oxa-Michael-Michael reaction between one of the synthesized alkenylisatins and 2-hydroxycinnamaldehyde. Currently, new methodologies that allow access to spirooxindole scaffolds are being explored, mainly though Diels-Alder reactions between 2-methylenindolin-2-ones and aldehydes via the trienamine activation mode. The following cascade reactions will be explored in the future to obtain the proposed polycyclic spirooxindole derivatives.

Keywords

• spirooxindoles
• organocatalysis
• 3-methylenindolin-2-one
• ApDOS