Assembly of fused indenes via Au(I)-catalyzed C1-C5 cyclization of enediynes bearing an internal nucleophile.

A tandem reaction initiated by Au(I)-catalyzed C1-C5 cyclization of enediynes bearing an internal carboxy nucleophile has been developed, providing a distinctive methodology for the assembly of fused indenes including indeno[1,2-c]isochromen-5(11H)-ones and indeno[1,2-b]pyran-2(5H)-ones. A mechanism involving the concerted formation of the five- and six-membered rings was proposed.