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.