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[3,4-d]­[1,2,3]­triazines and dihydrotriazines exhibit good fluorescence
activity.