Alkylruthenium complexes

Hydroxycarbonylation of olefins (Scheme 5.11) in fully aqueous solution was studied using a rathenium-carbonyl catalyst with no phosphine ligands [35]. In a fine mechanistic study it was shown, that (the WGS) reaction of /ac-[Ru(C0)3(H20)3] and water provided /ac-[RuH(C0)2(H20)3]. At 70 °C and in the presence of CF3SO3H the latter compound reacted with ethene (10 bar) giving a a-alkylruthenium complex, solutions of which absorbed CO and yielded the corresponding acyl-derivative ... 

Monohydride 44, with its vacant site now available, can bind to the alkene, giving 45, which can then undergo 1,2-insertion to form alkylruthenium complex 46. Finally, heterolytic cleavage with H2 regenerates the catalyst and gives the alkane (Scheme 9.8). 

Alkylruthenium complexes Hu2 have been also designed for TPA (Fig. 22). Linear absorption properties show a weak bathochromic shift from the... 

Table 5. ct-Alkylruthenium Complexes from Insertion OF Alkenes into the Ru—H Bond of [RuH(NH3)5][S04]. 

Hydroquinone was beneficial to the reaction outcome, its effect being attributed to the suppression of radical side-reactions. The proposed mechanism consists of iniHal electrophilic attack of the metal onto the C—H bond of the arene to give an arylruthenium species with concomitant proton release, followed by alkene insertion into the Ru—C bond, -hydride elimination to liberate the cinnamate and a ruthenium hydride, and finally regeneration of the active catalyst either by insertion of another alkene into the Ru-H bond protonation of the alkylruthenium complex and elimination of methyl propionate (under an... 

NMR for the reaction of a hydrido( -cyclohexadienyl)cyclohexene complex of ruthenium(II) . Insertion of both activated and unactivated alkenes into the Ru—H bond of K[(PPh3)2Ph2PCgH4RuH2] CioHg (C2H5)20 also occurs, although isolable (T-alkylruthenium species are not yet characterized . 

Cationic pentaaminoruthenium hydride complexes also undergo facile formation of alkylrutheniums in reactions with both simple and halogenated alkenes (see Table 5) ... 

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