Novel Double [3 + 2 + 1] Heteroannulation for Forming Unprecedented Dipyrazolo-Fused 2,6-Naphthyridines

A novel four-component strategy for the efficient synthesis of unprecedented dipyrazolo-fused 2,6-naphthyridines through a double [3 + 2+1] heteroannulation has been described. The bond-forming efficiency, accessibility, and generality of this synthesis make it highly valuable to assemble tetra-heterocyclic scaffolds.