Squaramide-catalyzed asymmetric Michael/cyclization cascade reaction of 3-isothiocyanato oxindoles with chalcones for synthesis of pyrrolidinyl spirooxindoles

A highly efficient method for the construction of pyrrolidinyl spirooxindoles with 3-isothiocyanato oxindoles and chalcones via a Michael/cyclization cascade reaction has been developed by using bifunctional cinchona-derived squaramide organocatalysts. A series of complex pyrrolidinyl spirooxindoles could be obtained in high yields (up to 99%) with excellent diastereo- and enantioselectivities (up to >99 : 1 dr, >99% ee) under mild conditions.