Gold‐Catalyzed Intramolecular Reaction of Indoles with Alkynes: Facile Formation of Eight‐Membered Rings and an Unexpected Allenylation

Abstract

Going for gold: Cationic gold(I) complexes favor formation of six- and seven-membered rings by 6-endo-dig, 6-exo-dig, and 7-exo-dig cyclizations of alkynyl indoles, whereas indoloazocines are favored with AuCl3 as catalyst (see scheme). Allenes are also formed by a fragmentation process.