Nitriles homogeneous catalysis

CO oxidation, 38 236 differential heat of adsorption, 38 217 Biphasic systems, catalysis see Multiphase homogeneous catalysis BiPMo catalysts, 34 39 in formamide to nitrile reaction, 34 39 Bi-postdosing thermal desorption spectroscopy cyclohexene, 42 240... 

The addition of HCN to olefins catalyzed by complexes of transition metals has been studied since about 1950. The first hydrocyanation by a homogeneous catalyst was reported by Arthur with cobalt carbonyl as catalyst. These reactions gave the branched nitrile as the predominant product. Nickel complexes of phosphites are more active catalysts for hydrocyanation, and these catalysts give the anti-Markovnikov product with terminal alkenes. The first nickel-catalyzed hydrocyanations were disclosed by Drinkard and by Brown and Rick. The development of this nickel-catalyzed chemistry into the commercially important addition to butadiene (Equation 16.3) was conducted at DuPont. Taylor and Swift referred to hydrocyanation of butadiene, and Drinkard exploited this chemistry for the synthesis of adiponitrile. The mechanism of ftiis process was pursued in depth by Tolman. As a result of this work, butadiene hydrocyanation was commercialized in 1971. The development of hydrocyanation is one of tfie early success stories in homogeneous catalysis. Significant improvements in catalysts have been made since that time, and many reviews have now been written on this subject. ... 

The comparison with homogeneous catalysis by outersphere electron donors (benzonitrile anion radicals and similar nitriles or esters) clearly indicates that iitm("0 ) porphyrins act as chemical rather than redox catalysts in the reduction of CO2 the main product is different (CO instead of oxalate) and the catalytic efficiency is higher for the same standard potential of the catalyst couple. 

Stoichiometric amounts of tetraethylammonium cyanide react with aliphatic bromides in dichloromethane, acetonitrile or DMSO to give reasonable yields of the corresponding nitriles [13]. These reactions are clearly related to, but not actually examples of, phase transfer catalysis. It is interesting, however, that under these homogeneous conditions, tetraethylammonium cyanide reacts in acetonitrile with neopentyl bromide to give the corresponding nitrile (see Eq. 7.3). Bimolecular displacements on such sterically hindered substrates are usually quite difficult to effect. 

However, the most recent and useful applications of Pt catalysis to the hydrolysis of nitriles to amide were achieved with homogeneous platinum phosphinito catalysts [139, 140], The catalyst precursors are coordination compounds of Pt(ll) with secondary phosphine oxides and the results obtained with [PtH(PMe20H) (PMc2-0)2H] with aUcyl, alkenyl, and aryl nitriles are reported in Scheme 76. 

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