Iron(III)(salen)Cl as an efficient catalyst for synthesis of bis(indolyl)methanes

[Fe(III)(salen)]Cl (salen = N,N′-ethylenebis(salicylimine)) is an efficient catalyst for the electrophilic substitution of indole with carbonyl compounds to afford the corresponding bis(indolyl)methanes in good yields in molten tetrabutylammonium bromide as an ionic liquid. Notable features of this new procedure are shorter reaction times, cleaner reaction profiles, and simple experimental and work-up procedures.