Stereo‐ and Regioselective Construction of Spirooxindoles Having Continuous Spiral Rings via Asymmetric [3+2] Cyclization of 3‐Isothiocyanato Oxindoles with Thioaurone Derivatives

Abstract

A highly efficient enantioselective [3+2] cyclization of 3‐isothiocyanato oxindoles with thioaurone derivatives was explored for the synthesis of spirooxindoles containing continuous spiral ring structures. Three continuous spiral ring structures and three consecutive chiral centers (including two spiro quaternary stereocenters) were conveniently constructed at a time. In addition, an uncommon sulfur‐containing spirocyclic ring was constructed at the same time. The reaction went smoothly whether the alkenyl moiety of thioaurone derivatives was at 2‐position (up to 99 % yield, up to 99 % ee, up to > 20:1 dr) or at 3‐position (up to 96 % yield, up to 95 % ee, up to 12:1 dr).