Aluminium-exchanged tungstophosphoric acid: An efficient catalyst for intermolecular hydroarylation of vinyl arenes

Aluminium-exchanged tungstophosphoric acid catalyst was prepared and characterized by FT-infrared, Laser-Raman and X-ray photoelectron spectroscopy. The spectral results suggest the retention of Keggin ion structure of tungstophosphoric acid even after exchange of alumina with its protons. The catalyst was studied for intermolecular hydroarylation of styrene derivatives with various electron rich arenes under mild and solvent-free reaction conditions. The present protocol offers an environmentally benign process for the synthesis of 1,1-diarylethanes, and the catalyst can be recovered easily and reusable without any considerable loss in activity.