Asymmetric Michael/Cyclization Cascade Reaction of 3-Isothiocyanato Oxindoles and 3-Nitroindoles with Amino-Thiocarbamate Catalysts: Enantioselective Synthesis of Polycyclic Spirooxindoles

An unprecedented organocatalytic asymmetric Michael/cyclization cascade reaction of 3-isothiocyanato oxindoles and. 3-nitroindoles has-been disclosed. A wide range of enantioenriched polycyclic, spirooxindoles, containing three contiguous chiral centers With two of them having quaternary stereocenters, could be smoothly obtained with satisfactory results (up to 99%-yield, >99:1 dr, and 96% ee). This methods very promising because the reaction is scalable, and the versatile transformations of the products into other spirocyclic oxindoles are also feasible.