Rh(III)-Catalyzed Oxidative Domino C–H/N–H Annulation: Diarylureas as Arylamine Donors for the Assembly of Indolo[2,1‑a]isoquinolines

An efficient and convenient Rh­(III)-catalyzed double aryl C­(sp2)–H bond and N–H activation and annulation reaction is reported for the synthesis of indolo­[2,1-a]­isoquinolines in the presence of the Cu­(OAc)2 oxidant under heating conditions. Distinct from previous works with other arylamine donors, one molecule of 1,3-diarylurea can serve as a precursor of two molecules of arylamine in the reaction with diaryl-substituted alkynes.