Cyclooctatriene complexes with ruthenium

Cyclooctatetraene (continued) with iron, 12 267-273 with nickel, 12 307, 308 with palladium, 12 315 with platinum, 12 319 with rhodium, 12 304 with ruthenium, 12 280 with silver, 12 340, 342, 343, 346 complexes of, 4 81 iron complexes of, 4 89 Cyclooctatriene complexes... 

Acetylenic compounds form adducts with acrylic acid derivatives, catalysed by a ruthenium complex with 1,5-cyclooctadiene (cod) and 1,3,5-cyclooctatriene (cot), as shown in reaction 10. ... 

Direct evidence for the oxidative addition of allyl carboxylates to a zero-valent ruthenium complex with the allyl-0 bond cleavage, has been obtained by the reaction of Ru(cod)(cot) (cot = 1,3,5-cyclooctatriene) with allyl carboxylates in the presence of tertiary phosphine under ambient conditions to give Ru(OCOR)()7 -C3H5)L3 [55], where Ru( 7 -C8Hio)L3 acts as an intermediate for the reaction (Scheme 3.29) [56]. 

Success was obtained with Ru3(CO)i2 as catalyst precursor [6], but the most efficient catalysts were found in the RuCl2(arene)(phosphine) series. These complexes are known to produce ruthenium vinylidene spedes upon reaction with terminal alkynes under stoichiometric conditions, and thus are able to generate potential catalysts active for anti-Markovnikov addition [7]. Similar results were obtained by using Ru(r]" -cyclooctadiene)(ri -cyclooctatriene)/PR3 as catalyst precursor [8]. (Z)-Dienylcarba-mates were also regio- and stereo-selectively prepared from conjugated enynes and secondary aliphatic amines (diethylamine, piperidine, morpholine, pyrrolidine) but, in this case, RuCl2(arene) (phosphine) complexes were not very efficient and the best catalyst precursor was Ru(methallyl)2(diphenylphosphinoethane) [9] (Scheme 10.1). 

Ruthenium-catalyzed hydroacylation of 1,3-dienes with aromatic and heteroaromatic aldehydes occurs in relatively good yields to afford the corresponding fi, /-unsaturated ketones . Isoprene and benzaldehyde were treated with 4 mol% Ru(COD)(COT) (COD = 1,5-cyclooctadiene, COT = 1,3,5-cyclooctatriene) and 4 mol% PPhs under argon for 40 hours to give 54% 80 (equation 41). The key intermediate is an acyl- ) -(allyl)ruthenium complex which undergoes reductive elimination to give the corresponding... 

Dien-4-ynes 136 (R -R = alkyl) are produced from propargylic carbonates 135 and terminal alkynes in the presence of a palladium-phosphine complex and copper(I) iodide. The linear co-dimerization of terminal acetylenes and 1,3-dienes is catalyzed by ruthenium(cyclooctadiene)(cyclooctatriene)(trialkylphosphine) (alkyl = Et, Bu or octyl) thus 1-hexyne and methyl penta-2,4-dienoate give a mixture of the eneynes 137 and 138. Coupling of octa-l,7-diyne (139) with the acetylenic bromo acid 140 in aqueous THF-methanol containing butylamine, hydroxylamine hydrochloride and copper(I) chloride gave a mixture of the triynyl acids 141 and 142. ... 

Oxidative addition of allyl and vinyl ethers to zero-valent ruthenium complex also takes place under mild conditions. The reaction of Ru(cod)(cot) [cod = 1,5-cyclooctadiene, cot = 1,3,5-cyclooctatriene] with allyl phenyl ether or phenyl ortho-tolyl ether in the presence of PMea results in cleavage of the C-0 bond to give a (r -allyl)(aryloxo)ruthenium(II) complex, Ru(OAr)(r/ -C3H5)(PMe3)3 (Scheme 3.40) [77]. When allyl 2,6-xylyl ether is employed in this reaction, further C-H bond activation takes place to give an oxaruthenacycle... 

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