Ruthenium(II)‐Catalyzed C−H Bond [3+2] Annulation of N‐Nitrosoanilines with Alkynes in Water

Abstract An efficient Ru II ‐catalyzed C−H bond redox‐neutral annulation of N‐nitrosoanilines with alkynes by employing water as the solvent has been developed. This transformation provides an easy and robust protocol for the synthesis of indoles with a broad range of functional group tolerance and excellent regioselectivity.