Trifluoromethanesulfonic acid-catalyzed solvent-free bisindolylation of trifluoromethyl ketones

A trifluoromethanesulfonic acid-catalyzed solvent-free bisindolylation reaction of indoles with alkyl and aryl trifluoromethyl ketones has been developed. The trifluoromethyl-substituted bisindolylalkane derivatives were synthesized in moderate to excellent yields.