Isolation of trans-2,5-Bis(methoxycarbonyl)ruthenacyclopentane by Oxidative Coupling of Methyl Acrylate on Ruthenium(0) as an Active Intermediate for Tail-to-Tail Selective Catalytic Dimerization

The trans-bis(methoxycarbonyl)ruthenacyclopentane complex [trans-Ru{(CH)-H-2{C(O-1)OMe} (CH2CH2C5)-H-3-H-4 H-{C(O-2)OMe}-kappa C-1(2), kappa O-1(1), kappa C-1(5), mu-kappa O-1(2)} (eta(4)-1,5-COD)](2) (2) and the acetonitrile adduct Ru[(CH)-H-2(CO2Me)(CH2CH2CH)-H-5(CO2-Me)-kappa C-1(2),kappa C-1(5)](eta(4)-1,5-COD)(NCMe)(2) (3) have been obtained from the reaction of Ru(eta(6)-naphthalene)(eta(4)-1,5-COD) (1) with methyl acrylate and are active for the Ru(0)-catalyzed dimerization of methyl acrylate. Thus, complex 3 catalyzes the tail-to-tail dimerization of methyl acrylate in 52% yield at 140 degrees C in THF, suggesting that this dimerization proceeds by the oxidative coupling mechanism.