Copper-Catalyzed Domino Annulation of Isoselenocyanates: A Pathway to Structurally Diverse N, Se-Bis-Heterocyclic, and Fused Heterocyclic Compounds

A copper-catalyzed domino addition/cyclization reaction was developed to synthesize novel benzoselenazole-linked 1,2,3-triazole and tetracyclic fused 12H-benzo[4,5]selenazole[2,3-b]quinazolin-12-one derivatives from isoselenocyanates. This domino reaction efficiently constructed multiple new chemical bonds in a single step, forming either four (one C–Se and three C–N) or three (one C–Se and two C–N) bonds. The reaction offers several key advantages, including mild conditions, broad substrate compatibility, and straightforward and safe operation. It presents a new method for synthesizing N, Se-containing polycyclic compounds, which have potential interest in medicinal chemistry. Notably, some of the synthesized compounds exhibited anticancer activity with IC50 values below 20 μmol L–1 against T24 human bladder cancer cells.