Ru(II)-Catalyzed C-H Activation/[4+2] Annulation of Sulfoxonium Ylide with Maleimide: Access to Fused Benzo[]isoindole-1,3,5-trione.

A ruthenium-catalyzed C-H activation and a concomitant [4+2] annulation of sulfoxonium ylide with maleimide have been demonstrated. This tandem reaction results in the formation of fused benzo[]isoindole-1,3,5-trione. The method employs mild conditions and is free of metal oxidants. The reaction pathway predominantly involves protodemetalation over β-hydride elimination due to the lack of β-hydrogens.