Pd-catalyzed [3 + 2] cycloaddition of cyclic ketimines and trimethylenemethanes toward N -fused pyrrolidines bearing a quaternary carbon.

A Pd-catalyzed [3 + 2] cycloaddition of N -sulfonyl cyclic ketimines and trimethylenemethanes (TMM) was developed that afforded N -fused pyrrolidines bearing a quaternary carbon. Under mild reaction conditions, structurally diverse N -sulfonyl cyclic imines, including sulfamate-fused aldimines, aryl- or styryl-substituted sulfamate-derived ketimines, and N -sulfonyl cyclic ketimines, were tolerated as reactants, affording N -fused pyrrolidines with high efficiency.