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}-κ¹C²,κ¹O¹,κ¹C⁵,μ-κ¹O²}(η⁴-1,5-COD)]₂ (2) and the acetonitrile adduct Ru[C²H(CO₂Me)CH₂CH₂C⁵H(CO₂Me)-κ¹C²,κ¹C⁵](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.