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

Abstract

The trans-bis(methoxycarbonyl)ruthenacyclopentane complex [trans-Ru{C 2 H{C(O

Oxidative coupling reactions at ruthenium(0) and their applications to catalytic homo- and cross-dimerizations¶

“…Recrystallization of the extremely air-sensitive powder from cold THF gave single crystals of a dinuclear ruthenacyclopentane 2 in 67% yield based on the Ru atom (Scheme 5) [61]. Although theyield was not particularly high, this result provides the first solid evidence for the oxidative coupling mechanism for dimerization of substituted alkenes.…”

Mechanistic insights into catalytic linear cross-dimerization between conjugated dienes and styrenes by a ruthenium(0) complex

“…We have documented a series of homo-and cross-dimerization reactions between conjugated compounds and/or substituted alkenes by a Ru(0) catalyst. A considerable mechanistic breakthrough was isolation of a ruthenacyclopentane, trans-[Ru[C 1 H(CO 2 Me)C 2 H 4 C 4 H(CO 2 Me)-κ 2 -C 1 ,C 4 ](η 4 -1,5-COD)(NCMe) 2 ] out of the reaction of [Ru(η 6 -naphthalene)(η 4 -1,5-COD)] (1) with methyl acrylate (Scheme 1), and the isolated ruthenacyclopentane also catalyzed tail-to-tail dimerization of methyl acrylate [7].…”

Synthesis of conjugated diene complexes of ruthenium(0) derived from Ru(η6-naphthalene)(η4-1,5-COD): Z to E isomerisation of coordinated 1,3-pentadiene

“…The lability of the coordinated naphthalene in [Ru(h 6 -C 10 H 8 )(h 4 -1,5-COD)] (1) [1e3] is responsible for the ability of this complex, especially in the presence of acetonitrile, to catalyse some important organic reactions, including alkene hydrogenation [3] and isomerisation [4,5], the selective tail-to-tail dimerisation of unsaturated compounds such as methyl acrylate [6,7], methyl methacrylate [8] and acrylonitrile [9], and cross dimerisations between butadiene and methyl methacrylate [10], and between 2,5-dihydrofuran and methyl methacrylate [11]. An excess of butadiene in the absence of acetonitrile completely displaces naphthalene from complex 1 to give supine, prone-[Ru(h 3 :h 3 -2,6-octadiene-1,8-diyl)(h 4 -1,5-COD)] as a result of oxidative coupling of the butadiene units in an intermediate [Ru(h 4 -cisoid-butadiene)(h 2 -transoid-butadiene)(h 4 -1,5-COD)] that can be detected at low temperature [12].…”