Ruthenium-ethylene complex

The homobimetallic, ethylene-ruthenium complex 15, which contains three chloro bridges, was readily obtained from the reaction of [RuCl2(/ -cymene)]2 with 1 atm of ethylene [34]. In 2009, Demonceau and Delaude [34] showed that complex 15 could be a useful precursor to allow subsequent access to the diruthenium vinylidene complex 16, allenylidene complex 17, and indenylidene complex 18 (Scheme 14.8). Upon reaction with propargylic alcohol, complex 15 afforded vinylidene complex 16, which converted into the allenylidene complex 17 in the presence of molecular sieves [34]. As shown in the acid-promoted intramolecular rearrangement of mononuclear ruthenium allenylidene complexes [19, 20, 32], the addition of a stoichiometric amount of TsOH to complex 17 at -50 °C led to the indenylidene binuclear complex 18 [34]. Complex 18 has been well... 

Arylamine couplings with ethylene are catalyzed by ruthenium complexes (Equation (103)).97... 

Addition of disulfides to carbon-carbon double bonds is catalyzed by ruthenium complexes (Equation (71)).204 Even relatively less reactive dialkyl disulfides add to norbornene with high stereoselectivity in the presence of a catalytic amount of Cp RuCl(cod). Diphenyl disulfide adds to ethylene and terminal alkenes under identical conditions (Equation (72)). 

Intermolecular enyne metathesis has recently been developed using ethylene gas as the alkene [20]. The plan is shown in Scheme 10. In this reaction,benzyli-dene carbene complex 52b, which is commercially available [16b], reacts with ethylene to give ruthenacyclobutane 73. This then converts into methylene ruthenium complex 57, which is the real catalyst in this reaction. It reacts with the alkyne intermolecularly to produce ruthenacyclobutene 74, which is converted into vinyl ruthenium carbene complex 75. It must react with ethylene, not with the alkyne, to produce ruthenacyclobutane 76 via [2+2] cycloaddition. Then it gives diene 72, and methylene ruthenium complex 57 would be regenerated. If the methylene ruthenium complex 57 reacts with ethylene, ruthenacyclobutane 77 would be formed. However, this process is a so-called non-productive process, and it returns to ethylene and 57. The reaction was carried out in CH2Cl2 un-... 

Ruthenium complexes mediate the hydroamination of ethylene with pyridine.589 The reaction, however, is not catalytic, because of strong complexation of the amine to metal sites. Iridium complexes with chiral diphosphine ligands and a small amount of fluoride cocatalyst are effective in inducing asymmetric alkene hydroamination reaction of norbomene with aniline [the best enantiomeric excess (ee) values exceed 90%].590 Strained methylenecyclopropanes react with ring opening to yield isomeric allylic enamines 591... 

The same ethylidene ruthenium complex, as well as its iron congener, is alternatively obtained through direct protonation of the dimetallacycles 64a (M = Fe) and 64b (M = Ru) (64). In this case, the carbonyl alkyne carbon-carbon bond is broken irreversibly to give the cationic /x, 17s-vinyl complexes 65a and 65b, which undergo nucleophilic attack by hydride (NaBFLi) to produce complexes of methylcarbene (63a,b) (Scheme 21a). Deuterium-labeling experiments prove that the final compounds arise from initial hydride addition to the /3-vinylic carbon of 65. However, isolation of small amounts of the 7j2-ethylene complex 66 indicates that hydride attack can also occur at the a-vinylic carbon (64). 

Several related examples of transition metal-catalyzed addition of C-H bonds in ketones to olefins have been reported (Table 2) [11-14]. The alkylation of diterpenoid 6 with olefins giving 7 proceeds with the aid of Ru(H)2(CO)(PPh3)3 (A) or Ru(CO)2(PPh3)3 (B) as catalyst [11], Ruthenium complex C, Ru(H)2(H2)(CO) (PCy3)2, has catalytic activity in the reaction of benzophenone with ethylene at room temperature [12]. The alkylation of phenyl 3-pyridyl ketone 8 proceeds with A as catalyst [13], Alkylation occurs selectively at the pyridine ring. Application of this C-H/olefin coupling to polymer chemistry using ce,co-dienes such as 1,1,3,3-tetramethyl-l,3-divinyldisiloxane 11 has been reported [14]. 

The ruthenium(II) - ethylene episulphide complex [152] may serve as a model for the coordination of tiiranes at the catalyst active site. 

Along with diene and diyne metathesis, ene-yne metathesis has also been employed to form macrocycles. This type of metathesis is performed with the catalysts used for olefin metathesis, and the yields are improved in the presence of ethylene, which forms the highly reactive [Ru]=CH2 species. Shair and coworkers took advantage of this reaction twice in the course of their total synthesis of longithorone A [40]. When ene-ynes 51 and 52 are treated with ruthenium complex G1 under an atmosphere of... 

An interesting aspect of the bis(methyl)ruthenium complexes 33 is their tendency to allow hydride abstraction with (Ph3C)PF6. They lead to ethylene complexes 55 and 56 (46,47).The X-ray structure of 55 shows bond distances of 1.411(13) A for C=C and 1.50 A for Ru—H (46,47). The reaction probably proceeds via intermediates 53 and 54, although it was not established whether the transformation 33 - 53 involves a mono-electronic process as with WMe2(C5H5)2 (48). A similar reaction from the deuterated derivative 57 gives exclusively complex 58, configurationally... 

RuCl2(arene)]2 complexes (1) react with 1,5-cyclooctadiene and 1,3- or 1,4-cyclohexadiene in the presence of ethanol and Na2C03 or zinc dust to give Ru°(776-arene)(V diene) compounds of type 196-198 in 60% yield [Eq. (20)] thus, this reaction appears to be the reverse of the 198-> 1 reaction [Eq. (19)]. The same reaction with ethylene leads to the bis-ethylene ruthenium(O) complex 205 (37%) (131,10). The norbornadiene complex 207 is prepared similarly from derivative 206 (125). Combination of transformations 206 - 207 [Eq. (21)] or 1 - 198 [Eq. (20)] with trans-... 

Hydroformylation can also be achieved using ruthenium complexes such as Ru(CO)3(PPh3)2, by platinum-tin catalysts,59 and by PtH(Ph2POH)(PPh3) made from Pt(COD)2, PPh3, and Ph2POH. The latter system yields ketones when under high ethylene pressure. Ketone formation can also be observed in other systems and occurs by the reaction sequence ... 

Catalytic transformations involving the C-H bonds of thiophene are rare, but recently there has been a report on the catalytic addition of the C(2)-H bond of thiophene across ethylene to form 2-ethylthiophene <20040M5514>. Reaction of the ruthenium complex TpRu(CO)(NCMe)(Me) (where Tp = hydrido tris(pyrazolyl)borate) with thiophene produces the 2-thienyl complex 249 and methane. This complex catalyzes the formation of 2-ethylthiophene from a solution of thiophene and ethylene (Equation 121). The mechanism of this reaction has been explored. 

For the intermolecular hydroacylation of olefins and acetylenes, ruthenium complexes - as well as rhodium complexes - are effective [60-64]. In 1980, Miller reported the first example of an intermolecular hydroacylation of aldehydes with olefins to give ketones, during their studies of the mechanism of the rhodium-catalyzed intramolecular cydization of 4-pentenal using ethylene-saturated chloroform as the solvent [60]. A similar example of the hydroacylation of aldehydes with olefins using ruthenium catalyst is shown in Eq. 9.43. When the reaction of propionaldehyde with ethylene was conducted in the presence of RuCl2(PPh3)3 as the catalyst without... 

When ethanol is produced, methanol is formed in the first step, and is then homologated. Dombek reported that ruthenium complexes are effective for the production of ethylene glycol at 340 atm and below, especially in the presence of iodide (Eq. 11.4) [11]. 

Knifton reported that the combination of ruthenium complex/phosphonium salt, such as Ru02/Bu4PBr and Ru(acac)3/Bu4PBr, is a good catalyst for the synthesis of ethylene glycol together with methanol and ethanol [12]. 

The coupling reaction between phenol and ethylene to give ortho-ethylphenol is catalyzed by (triphenylphosphite)ruthenium complex [20]. In this reaction, the ortho C-H bond of triphenylphosphite is cleaved by orthometallation, and then insertion of ethylene followed by reductive elimination lead to the formation of triarylphos-phite having an ortho-ethylphenoxo group. Transesterification between the phosphite and phenol then releases (ortho)-ethylphenol by reproducing triphenylphosphite (Scheme 14.8). 

Quenching of Ru(bipy)32+ by the organic cations trans-1,2-bis(N-methYl-4-pyridyl)ethylene and l,l -dimethy 1-4,4 -bipyridine (paraquat ) and by the transition metal ion complexes Fe(H20)g and Ru(NH3) 3+ occurs at near diffusion controlled rates (241). In all four cases flash studies indicated that electron transfer is a principal component of the quenching mechanism. Selective excitation of Ru(bipy)3 in the presence of these quenchers (Qqx produced the oxidized ruthenium complex, Ru(bipy)33+, and the reduced quencher, Qj-gd quenching... 

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