Catalysts ruthenium complexes

Scheme 5.5. Enantioselective Hydrogenation with Ruthenium Complex Catalysts... 

Hydride ion transfer from formic acid and its salts finds widespread application in the reduction of organic substrates, but limited use has been made of the procedure under phase-transfer catalytic conditions. However in the presence of a ruthenium complex catalyst, it is possible to selectively reduce the C=C bonds of conjugated ketones with sodium formate [11], The rate of reduction is fastest with tetrahexyl-ammonium hydrogensulphate and Aliquat the complete reduction of chalcone being effected within one hour, whereas with benzyltriethylammonium chloride only ca. 15% reduction is observed after two hours under similar conditions. 

Colonge Brvnie Bull. Soc. Chim. Fr. 1963, 1799. For an example with basic catalysis, see Hoffmann Kover. Pauluth J. Chem. Soc., Chem. Common. 1985, 812. For an example with a ruthenium complex catalyst, see Trost Kulawiec Tetrahedron Lett. 1991,32, 3039. 

If water is present, and a ruthenium complex catalyst is used, the addition of a... 

The selective hydrogenation of a,/3-unsaturated aldehydes to give the corresponding unsaturated alcohols [Eq. (9)] was investigated with the ruthenium complex catalysts, initially present as [Ru(H)(Cl)(tppts)3] or [Ru(H)2(tppts)4] (91). 

A range of variously substituted piperidines, piperazines and dialkylamines have been conveniently deuterated in a single step by isotopic exchange with deuterium oxide in the presence of an appropriate ruthenium complex catalyst.154 The isotopic exchange has been carried out efficiently in dimethylsulfoxide at positions both a and P to the NH group. 

A variety of other oxidants that produce sulfoxides from sulfides are known, such as nitric acid, acyl nitrates, nitronium salts,N204, oxygen with ruthenium complex catalysts, - pressurized oxygen with CAN as a catalyst, ozone, - TTN, Ce salts, - and potas-... 

Oxidation with Ruthenium Complex Catalysts and Oxidants I 69... 

The hydroformylation reaction or 0x0 process is an important industrial synthetic tool. Starting from an alkene and using syngas, aldehydes with one or more carbon atoms are obtained. In almost all industrial processes for the hydroformylation of alkenes, rhodium or cobalt complexes are used as catalysts [33]. A number of studies on ruthenium complex-catalyzed hydroformylation have been reported [34]. One of the reasons for the extensive studies on ruthenium complex catalysts is that, although the rhodium catalysts used in industry are highly active, they are very expensive, and hence the development of a less-expensive catalytic system is required. Since inexpensive ruthenium catalysts can achieve high selectivity for desired u-alde-hydes or n-alcohols, if the catalytic activity can be improved to be comparable with that of rhodium catalysts, it is possible that a ruthenium-catalyzed 0x0 process would be realized. 

Supported platinum, rhodium, and ruthenium complex catalysts have been used extensively in the reaction of trisubstituted silanes with acetylene in the gas phase, predominantly in a continuous-flow apparatus. Formation of a polymer layer on the surface after immobilization of the platinum complex has protected the catalyst against leaching in long-term hydrosilylation tests [91]. 

FIGURE 2 Comparison of methanol carbonylation rates as a function of water concentration for rhodium-complex, iridium-complex, and iridium/ruthenium-complex catalysts (190 °C, 28 bar, 30% MeOAc (w/w), 8.4% Mel (w/w), 1950 ppm Ir or equimolar Rh). Adapted with permission from Figure 1 in reference [125], copyright 2004, American Chemical Society. 

Carbapenetns having a conjugated diene system are obtained from suitably 1,4-disubstituted p-lactams 83 by use of a ruthenium complex catalyst. The unsaturated system can be of use in the formation of tricyclic nuclei . 

Ru3(CO)i2 reacts with dppe in benzene solvent to provide Ru(CO)3(dppe) Sanchez-Delgado RA, Bradley JS, Wilkinson G (1976) Further smdies on the homogeneous hydroformylation of alkenes by use of ruthenium complex catalysts. J Chem Soc Dalton Trans 399-404... 

Concepcion JJ, Tsai MK, MuckermanJT, Meyer TJ. Mechanism of water oxidation by single-site ruthenium complex catalysts. Chem Soc. 2010 132 1545-1557. 

The selective cleavage of carbon-carbon bonds in sugars can be achieved under relatively mild hydrogenolytic conditions using a ruthenium complex catalyst thus, besides D-mannitol and D-glucitol, D-fructose yielded up to 30% of glycerol. ... 

---