W(II)-catalyzed hydroarylation of bicyclo[2.2.1]hept-2-ene by simple arenes

The tungsten(II) carbonyl compound (CO)4W(μ-Cl)3W(SnCl3)(CO)3 has been found to be a very effective catalyst for the hydroarylation of bicyclo[2.2.1]hept-2-ene (norbornene) conducted in arene solution at room temperature. Norbornene adducts with benzene, toluene, para-xylene, and mesitylene have been isolated and their structures have been unambiguously established by means of 1H and 13C NMR spectroscopy. On the basis of 1H NMR monitoring of several catalytic reactions, a possible mechanism involving coordination of norbornene to the W(II) atom and its activation has been proposed.