Palladium-catalyzed three-component annulation reaction involving multiple C-H activation

The Pd-catalyzed ring-forming reaction via multiple C-H activation provides an efficient strategy to access cyclic ring systems. The current reactions are primarily restricted to single- and two-component reactions. Herein, we report a ring-forming reaction via palladium-catalyzed three-component multiple C-H activation. Using TsOMe as the methylating reagent, aryl iodides undergo maleimide-relayed C-H methylation. Subsequent cyclization via C(sp3)-H activation forms succinimide-fused tricyclic scaffolds. Depending on aryl iodides, the reaction involves dual or triple C-H activation to form two or three new C-C bonds. The reaction represents a new strategy for C-H methylation and offers a new synthetic method using simple and readily available substrates for succinimide-fused tricyclic scaffolds, which are crucial structural motifs found widely in organic compounds with diverse biological activities.