Asymmetric Organocatalytic Cascade Synthesis of Tetrahydro­furanyl Spirooxindoles

An enantio- and regioselective organocatalytic cascade starting from isatin has been disclosed to construct tetrahydrofuranyl spirooxindoles in high yields and stereoselectivities. Also, a triple cascade leading to the pentacyclic compound with two quaternary and a tertiary stereocenter is described. The reactions were catalyzed by cinchonine-based thiourea.