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{C2H{C(O1)OMe}C3H2C4H2C5H{C(O2)OMe}-κ1C21O11C5,μ-κ1O2}(η4-1,5-COD)]2 (2) and the acetonitrile adduct Ru[C2H(CO2Me)CH2CH2C5H(CO2Me)-κ1C21C5](η4-1,5-COD)(NCMe)2 (3) have been obtained from the reaction of Ru(η6-naphthalene)(η4-1,5-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 °C in THF, suggesting that this dimerization proceeds by the oxidative coupling mechanism.