Key to the success of Pd-catalyzed α-arylation of oxindoles in continuous flow involved a biphasic system, a precatalyst, and a packed-bed microreactor. Furthermore, this reaction was integrated into a two-step continuous-flow sequence for rapid, modular, and efficient syntheses of 3,3-disubstituted oxindoles.
“Continuous-flow synthesis of 3,3-disubstituted oxindoles by a palladium-catalyzed α-arylation/alkylation sequence”, Angew. Chem. Int. Ed., 2011, 50(28), 6396-6400.