Gold-Catalyzed Concomitant [3+3] Cycloaddition/Cascade Heterocyclization of Enynones/Enynals with Azides Leading to Furanotriazines

[Au]-catalyzed [3 + 3] cycloaddition reaction of enynones/enynals with azides, which allows the efficient regioselective synthesis of highly fused furo[3,4-d][1,2,3]triazines in good-to-excellent yields under mild conditions, has been developed. The synthetic utility of furanotriazines was exploited by oxidation with cerium ammonium nitrate (CAN) affording highly functionalized dihydrotriazines. Both furo[,4-d][1,2,3]triazines and dihydrotriazines exhibit good fluorescence activity.