Hydrovinylation of alkenes catalyzed by the ruthenium-hydride complex formed in situ from (PCy3)2(CO)RuHCl and HBF4•OEt2

A ruthenium-hydride complex, generated in situ from the reaction of (PCy3)(2)(CO)RuHCl (1) with HBF4. OEt2, was found to be an effective catalyst for the hydrovinylation of alkenes. For example, the reaction of styrene with ethylene in, the presence of 1/HBF4. OEt2 (0.5 mol %) at room temperature produced the hydrovinylation product in 93% isolated yield. Both terminal alkenes and dienes were found to give the hydrovinylation products. Higher reaction temperature was required for the phenyl-substituted internal alkenes, in which cases the isomerized products were obtained.