Synthesis of Spiro 3,3′-Cyclopropyl Oxindoles via Cyclopropanation of 3-Alkenyl-oxindoles with CF3-Imidoyl Sulfoxonium Ylides

-imidoyl sulfoxonium ylides (TFISYs) for the construction of spiro 3,3'-cyclopropyl oxindoles has been achieved. A cascade intermolecular Micheal-addition reaction and intramolecular nucleophilic substitution sequence might be involved in the transformation, which afforded a wide range of multisubstituted spiro 3,3'-cyclopropyl oxindole products with high efficiency and diastereoselectivity.