Ruthenium(II)-Catalyzed Oxidative Double C-H Activation and Annulation Reaction: Synthesis of Indolo[2,1-a]isoquinolines.

The first metal-catalyzed double aryl C(sp2)-H bond activation of antipyrine and alkyne annulation reaction is reported. This Ru(II)-catalyzed reaction was accomplished in the presence of 20 mol % phosphine ligand tricyclohexylphosphine tetrafluoroborate to afford indolo[2,1-a]isoquinolines that are very important compounds because of their bioactivity and interesting optical properties.