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.

Azaanthraquinone assembly from N-propargylamino quinone via iodine-induced 6-endo-dig electrophilic cyclization.

An efficient methodology taking advantage of the excellent nucleophilicity of aminoquinone to assemble the azaanthraquinone framework was developed via an iodine-induced 6-endo-dig electrophilic cyclization. Therefore, starting from N-propargylaminoquinones, various 3-iodo-1-azaanthraquinones were obtained in yields ranging from 45% to 90%. The metal-free protocol features facile installation of an iodine atom on the azaanthraquinone ring and benign functional group compatibility.