Palladium catalyzed cascade umpolung allylation/acetalation for the construction of quaternary 3-amino oxindoles

Copper-Catalyzed Umpolung of N-2,2,2-Trifluoroethylisatin Ketimines for the Enantioselective 1,3-Dipolar Cycloaddition with Benzo[b]thiophene Sulfones

A copper-catalyzed umpolung of N-2,2,2-trifluoroethylisatin ketimines for the enantioselective 1,3-dipolar cycloaddition with benzo[b]thiophene sulfones was developed. Using a catalyst system consisting of an (S,S_p)-^tBu-Phosferrox ligand, Cu(OTf)₂, and Cs₂CO₃, a range of pentacyclic spirooxindoles containing pyrrolidine and benzo[b]sulfolane subunits were obtained in high efficiency with excellent regio-, diastereo-, and enantioselectivites under mild conditions. The practicality and versatility of the reaction were also demonstrated.