Commercially available simple ionic liquids-promoted dehydrative carbon–carbon bond-forming reaction of diarylmethanols and triarylmethanols with pyrroles,thiophene, furan and indoles

Two commercially available simple ionic liquids, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate and 1-ethyl-2,3-dimethylimidazolium trifluoromethansulfonate, effectively promote the solvent-free dehydrative carbon–carbon (C–C) bond-forming reaction of a variety of diarylmethanols and triarylmethanols with π-rich heteroaromatics, such as pyrroles, indole, furan, and thiophene without ring-opening and polymerization to give the corresponding not only 2-substituted pyrroles, furan, and thiophene but also 3-substituted indoles in good to excellent yields with moderate to excellent regioselectivities. These dehydrative C–C bond formation reactions of alcohols offer several advantages, such as the use of stoichiometric amounts of π-rich heteroaromatics and ionic liquids, water is the only by-product, there is no need for either organic solvents or expensive metal or strong Brønsted acid catalysts in the reaction, and the diversity of diarylmethylation and triarylmethylation.