Fe/Al pillared clay catalyzed solvent-free synthesis of bisindolylmethanes using diversely substituted indoles and carbonyl compounds

A fast, solvent-free solid acid mediated synthetic strategy for the synthesis of bisindolylmethanes has been developed. The process is applicable to a wide range of substrates with different protecting group survival properties. Reusability of Fe/Al pillared clay for more than 5 cycles without significant loss of catalytic activity adds to the features of the reaction.