Direct construction of fused indoles by gold-catalyzed cascade cyclization of conjugated diynes.

A gold-catalyzed cascade cyclization of aniline derivatives bearing a conjugated diyne moiety was developed. Following the 5-endo-dig indole formation, subsequent 7-endo-dig cyclization predominated over 6-exo-dig cyclization to give the indole fused with a seven-membered ring in good yields.