Synthesis of fused nine-membered rings: a simple protocol for synthesis of [1,2,3]-triazolo-[1,4]-benzoxazonine frameworks from the Baylis–Hillman acetates

A simple and facile protocol for synthesis of tricyclic [1,2,3]-triazolo-[1,4]-benzoxazonine derivatives has been developed from the Baylis–Hillman acetates by treatment with sodium azide followed by heating the resulting azido-alkyne in toluene under reflux [Huisgen reaction (click reaction)] in the absence of any copper salt.