Selenylation/Cyclization of 1‐(2‐(Allyloxy)aryl)‐1H‐indoles Access to Seleno‐Benzo[2,3][1,4]oxazepino[4,5‐a]indole Derivatives

The iron (ІІІ)‐promoted tandem cyclization of 1‐(2‐(allyloxy)aryl)‐1H‐indoles with diselenides has been developed for the preparation of seleno‐benzo[2,3][1,4]oxazepino[4,5‐a]indole derivatives. The investigation to determine the best reaction conditions indicated the use of 1‐(2‐(allyloxy)aryl)‐1H‐indoles (0.2 mmol) with diselenides (1.5 equiv) and iron(III) chloride (1.5 equiv) in acetonitrile at room temperature under air, and more than 40 examples were obtained. The reaction features access to selenized 7‐membered containing nitrogen‐oxygen heterocyclic skeleton, which also represents a 7‐exo‐trig cyclization process of 1‐(2‐((2‐methylallyl)oxy)aryl)‐1H‐indoles and diselenides.