A Base Promoted [3+2] Cycloaddition of Benzothiazolium Salts with Isoindigos to Synthesis N, S‐polyheterocyclic 3, 3′ Bispirooxindoles

Abstract A base promoted [3+2] cycloaddition of benzothiazolium salts with isoindigos has been developed, and a series of novel N, S‐polyheterocyclic 3, 3′ bispirooxindoles with four contiguous cycles and two spiro quaternary stereocenters have been successfully and effectively prepared in good to excellent yields (up to 99 %) under mild conditions.