Hydrogenation of alkenes with

The strategy of using two phases, one of which is an aqueous phase, has now been extended to fluorous . systems where perfluorinated solvents are used which are immiscible with many organic reactants nonaqueous ionic liquids have also been considered. Thus, toluene and fluorosolvents form two phases at room temperature but are soluble at 64 °C, and therefore,. solvent separation becomes easy (Klement et ai, 1997). For hydrogenation and oxo reactions, however, these systems are unlikely to compete with two-phase systems involving an aqueous pha.se. Recent work of Richier et al. (2000) refers to high rates of hydrogenation of alkenes with fluoro versions of Wilkinson s catalyst. De Wolf et al. (1999) have discussed the application and potential of fluorous phase separation techniques for soluble catalysts. 

Nelson, D. J., Li, R., and Brammer, C. (2005). /. Org. Chem. 70, 761. Article dealing with the correlation of hydrogenation of alkenes with ionization potentials. 

Enantiomeric Hydrogenation of Alkenes with Bidentate Ligand Systems... 

Hydrogenation of Alkenes with Croup III Metal and Lanthanide Complexes... 

Stoichiometric Ionic Hydrogenation of Alkenes with Metal Hydrides as the Hydride Donor... 

Enantioselective Hydrogenation of Alkenes with Ferrocene-Based Ligands... 

Table 6.6. Hydrogenation of alkenes with (ebthi)ZrMe2/MAO as precatalyst.

Pd, Pt, Rh, and Ru complexes were used as catalysts for the hydrogenation of alkenes with molecular hydrogen. In many cases, higher activity and enhanced selectivity for the desired reaction were accompanied hy successful re-use of the ionic liquid and the catalyst. Examples are reported for cyclohexadiene [10],... 

The formation of an complex has also been proposed to occur in the solid-liquid hydrogenation of alkenes with the supported hydrogen-bonded (SHB) catalyst [(sulphos)Rh(cod)]/Si02 (sulphos = 03S(C6H4)CH2C(CH2PPh2)3 cod = cyclo-octa-1,5-diene) (Scheme 10) [55-56]. 

Alternatively, the surface of a metal can be modified with an enantiomerically pure additive. For example, in 1956 palladium metal/silk fibroin was used for the hydrogenation of alkenes with moderate enantioselectivity. However, most success with modified metal siufaces has been achieved in the hydrogenation of ketones. The reduction of 3-keto esters with a Raney nickel/tartaric acid/sodium bromide catalyst provides good enantioselectivities. For example, P-keto ester (3.108) affords the P-hydroxy ester (3.109). Platinum metal modified with cinchona alkaloids has been successfully used with a-keto esters. The reaction yields product with up to 90% ee in the reduction of a-keto ester (3.110). ... 

Ionic hydrogenation of alkenes with triaUcylsUanes is possible in the presence of the strong acid T fOH, even at—75°C(eq 26)... 

Alkenes. There are only a few reports about enantioseleetive hydrogenation of alkenes with ruthenium complexes bearing / -stereogenic ligands. The substrates are the same as those used in rhodium-catalysed hydrogenations. Most of the results are Ksted in Table 7.7. 

Scheme 20 Hydrogenation of alkenes with calcium and strontium alkyl and hydride catalysts...

Answer The products are the same in the combustion reaction regardless of the hydrocarbon skeleton. Hydrogenation of alkenes with different hydrocarbon skeletons does not give the same saturated product. 

Scheme 6.4 Hydrogenation of alkenes with Rh-TPPTS in water.

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