Cobalt complexes maleic acid

The enzyme aconitase catalyzes the isomerization of citric acid to isocitric acid via the intermediate cis-aconitic acid (Scheme 46),530 and various attempts have been made to model this reaction.21 The cobalt Ill) complexes derived from methyl maleate (171) and methyl fumarate (172) have been prepared531 to study intramolecular attack by coordinated hydroxide on the alkene. Generation of the hydroxo species of the maleic acid complex leads to rapid cyclization to give the... 

Dialkyl cobalt complexes CocpR2(PPh3) react with methyl esters of maleic and fumaric acids to furnish compounds of the formula [Cocp(MeOOCCH = CHCOOMe) (PPh3)]. Chlorides of unsaturated carboxylic acids react with NaCo(CO)4 in the manner shown in scheme (6.68). The stability of complexes of the type... 

Rhodium(I) and cobalt(O) complexes of AMPHOS, [(nbd)Rh(AMPHOS)2] , and [Co(CO)3(AMPHOS)]2(PF6)2, were already being used in the early 1980s for the hydrogenation and hydroformylation of maleic and crotonic acid or styrene and 1-hexene in water or aqueous biphasic systems [49]. The lower effectiveness of the Co catalyst was attributed to the lighter metals proclivity to oxidation and phosphine... 

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