Asymmetric Synthesis of Spirooxindoles with Seven Stereocenters via Organocatalyzed One-pot Three-component Sequential Cascade Reactions

A bifunctional squaramide-catalyzed one-pot three-component Michael/Mannich-Michael/cyclization sequential cascade reaction for the construction of bispirooxindole-spirooxindoles was developed in good yields with excellent stereoselectivities (up to >20:1 dr, 99% ee). A series of original cinnamoyl-3-ylideneoxindoles have been applied to this sequential cascade strategy for the first time. This new strategy provides a process for the enantioselective construction of bispirooxindole-spirooxindoles with seven stereocenters, of which three are quaternary spiro-stereocenters. (Figure presented.).