An efficient and inexpensive visible light photoredox copper catalyst for N–N bond-forming reactions: the one-pot synthesis of indazolo[2,3-α]quinolines

An efficient and facile synthesis of indazolo[2,3-α]quinoline derivatives has been described which occur through Povarov reaction and tandem process of visible light-promoted intramolecular N–N bond formation using choline chloride/CuCl. This protocol is highly efficient and of low cost due to its mild reaction conditions, operational simplicity, applying inexpensive photoredox catalyst and overall good to excellent yields of various derivatives. Scale-up preparation of these heterocycles is also carried out.