Keggin Heteropoly Acid as a Green and Recyclable Catalyst for One-pot Synthesis of 1,1,3-Triheteroaryl Compounds

Green and one-pot procedure was reported for the preparation of 1,1,3-triheteroaryl compounds from indoles and α,β-unsaturated carbonyl compounds using heteropoly acid as a reusable heterogeneous catalyst. The desired products were obtained in high yields (60%–80%) at EtOH/H2O media. Keggin heteropoly acid catalyst can be reused for at least four times without significant loss in the catalytic activity and change of chemical structure. The catalyst recyclability, simplicity, environmental friendliness, and convenient operation of the reaction suggest the potential of the procedure as a real alternative to conventional reaction protocol.