Palladium-Catalyzed Route to Three-Component, One-Pot Sequential Synthesis of Functionalized Cyclazines: 2,2a1,4-Triazacyclopenta[cd]indenes

An efficient tandem route to the synthesis of 2,2a1,4‐triazacyclopenta[cd]indene derivatives of the cyclazine family has been developed. The target compounds were obtained in moderate to good yields by an ytterbium(III) triflate/palladium(II) acetate‐catalyzed three‐component domino reaction involving a palladium‐catalyzed intramolecular α‐arylation of an α‐aminocarbonyl functionality. This in turn will set the stage for a wide application of this useful reaction for the synthesis of structurally diverse polyheterocyclic skeletons containing the privileged imidazo[1,2‐a]pyridine structure.