Reactivity of Tungstenocene with BB and BH Bonds versus CH Bonds

The selectivity for addition of the BB bond of Cat'BBCat' (Cat' = 4-tBuC6H3O2) to [Cp2W] even in the presence of reactive CH bonds in the solvent benzene is remarkable. In contrast to facile BB cleavage, BH bond formation occurred upon photolysis of [Cp2W(H)(BCat)] (Cat = C6H4O2). This facile cleavage of BB bonds and the preferred formation of BH bonds contrasts with the typical selectivities for CC and CH activation reactions. The formation and some reactions of tungstenocene are shown on the right.