Tandem C‑2 Functionalization–Intramolecular Azide–Alkyne 1,3‑Dipolar Cycloaddition Reaction: A Convenient Route to Highly Diversified 9H‑Benzo[b]pyrrolo[1,2‑g][1,2,3]triazolo[1,5‑d][1,4]diazepines

An efficient diversity-oriented synthetic approach to annulated 9H-benzo­[b]­pyrrolo­[1,2-g]­[1,2,3]­triazolo­[1,5-d]­[1,4]­diazepines has been developed using a Sc­(OTf)3-catalyzed two-component tandem C-2 functionalization–intramolecular azide–alkyne 1,3-dipolar cycloaddition reaction. The reaction shows high substrate tolerance and provides a library of fused heterocycles that may lead to novel biologically active compounds or drug lead molecules.