Highly Efficient Enantioselective Construction of Bispirooxindoles Containing Three Stereocenters through an Organocatalytic Cascade Michael–Cyclization Reaction

Abstract

Bispirooxindole derivatives containing three stereocenters, including two spiro quaternary centers, were synthesized in a high-yielding, atypically rapid, and stereocontrolled cascade Michael-cyclization reaction between methyleneindolinones and isothiocyanato oxindoles catalyzed by a bi- or multifunctional organocatalyst. Mild conditions were used to construct bispirooxindoles with excellent enantio- and diastereomeric purities within less than 1 min. Catalyst reconfiguration offered access to the opposite enantiomer. This exceptionally highly efficient procedure will allow diversity-oriented syntheses of this intriguing class of compounds with potential biological activities.