Catalytic tail-to-tail dimerization of methyl acrylate using bis(triphenylphosphine)tricarbonyl ruthenium(0)

Abstract

The complex Ru(CO)3(PPla3)~ catalyzes the dimerization of methyl acrylate at 120-140~ to give taft-to-taft dimers containing predominantly dimethyl (E)-2-hexene-1,6-dioate together with small amounts of trimers and polymer. The reaction under hydrogen atmosphere selectively gave taft-to-taft dimers in improved yield without formation of trimers and polymer. Under these conditions a catalyst turnover number of 246 was obtained at 130~ in 6 h.

Catalytic Tail-to-Tail Selective Dimerization of Methyl Methacrylate Promoted by a Ruthenium(0) Complex

“…The tail-to-tail dimers of substituted olefins are potential precursors to monomers for condensation polymerization, and a variety of transition metal complexes have been documented to catalyze such tail-to-tail dimerization . Although such examples involve dimerization of methyl acrylate, acrolein, and acrylonitrile, the catalytic tail-to-tail dimerization of methyl methacrylate (MMA) is generally very difficult even though the product is potentially important . To the best of our knowledge, only a few examples have been reported of the dimerization of MMA by transition-metal-based catalysts, and the catalytic activities are generally poor.…”

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

“…This step is followed by 1,2-insertion of the second α-olefin into the resulting M−H bond, and subsequent reductive elimination then gives the tail-to-tail product. Mechanism B has been proposed for catalysis of dimerization promoted by RuCl 3 /Zn/MeOH, Cp*Ni(μ-CO)MoCp(CO) 2 , RuH 2 (PPh 3 ) 4 , and RuHCl(CO)(PPh 3 ) 3 in the case of methyl acrylate, by Ru(CO) 3 (PPh 3 ) 2 in the case of acrylonitrile, and by Ru(η 6 -C 6 H 6 )(η 4 -1,5-COD) in the case of acrolein. The oxidative coupling mechanism (mechanism C) also requires as precursor a low-valent metal species to which two α-olefins coordinate.…”