Highly Regio- and Diastereoselective Construction of Spirocyclopenteneoxindoles through Phosphine-Catalyzed [3 + 2] Annulation of Morita–Baylis–Hillman Carbonates with Isatylidene Malononitriles

Phosphine-catalyzed highly regio- and diastereoselective [3 + 2] annulation of Morita–Baylis–Hillman (MBH) carbonates with isatylidene malononitriles has been disclosed to give the corresponding spirocyclopenteneoxindoles in excellent yields under mild conditions. A plausible reaction mechanism has also been proposed on the basis of previous literature.