Montserrat Oliván and Kenneth G. Caulton
[Ru(H)2(H2)2L2] [L = P(C6H11)3] serves as a formal source of zerovalent ‘RuL2’, and undergoes unprecedented oxidative addition of both C–Cl bonds of CH2Cl2 to a single metal center, providing a convenient synthesis of the alkene metathesis catalyst [Ru(CH2)Cl2L2].