Hydrogenation of unsaturated acids

Hydrogenation of unsaturated acids and their methyl esters... 

Enantioselective Hydrogenation of Unsaturated Acid and Ester Derivatives... 

Enantioselective Hydrogenation of Unsaturated Acids and Esters 26.3.5.1 a,/ -Unsaturated Carboxylic Acids... 

The classic 1961 paper by Halpern et al. (the al. being John Harrod and myself) on the catalytic hydrogenation of unsaturated acids using chlororuthenium(II) species in aqueous acid solutions certainly motivated the work of Geoffrey Wilkinson s group on Ru- and Rh-triphenylphosphine hydrogenation catalysts these... 

In addition to the catalysts listed in Table 2, several rhodium(I) complexes of the various diphosphines prepared by acylation of bis(2-diphenylphosphinoethyl)amine were used for the hydrogenation of unsaturated acids as well as for that of pyruvic acid, aUyl alcohol and flavin mononucleotide [59,60]. Reactions were mn in 0.1 M phosphate buffer (pH = 7.0) at 25 °C under 2.5 bar H2 pressure. Initial rates were in the range of 1.6-200 mol H2/molRh.h. 

Fig. 16. Mechanism and hydrogen isotope exchange in the Ru-BINAP-catalyzed hydrogenation of unsaturated acids and esters, reflecting the author s views...

In the presence of aqueous NaOH, palladium(II) chloride was effective for the transfer hydrogenation of unsaturated acids, azlactones and phenylpyruvic acid (Scheme 3.36) at 65 °C although in quite long reaction times (typically 16 h) [255], For these water-soluble substrates organic solvents were not required. No attempt was made to clarify the nature of the active catalytic species, which -under these conditions- may well be a fine colloid of Pd metal. 

Although the carboxyl group was unaffected in the hydrogenations of unsaturated acids and esters described above, Sauer and Adkins192a succeeded in... 

Asymmetric hydrogenation. BPPM is an effective ligand for asymmetric hydrogenation of unsaturated acids of type 3 with the rhodium catalyst [Rh(l,5-hexadicnc)Cl]a. Optical yields of 83-91can be obtained when triethylamine is... 

Derivatives of carbohydrates that have been used to complex with rhodium catalysts to promote asymmetric hydrogenation include the phosphorus derivatives (6) and (7)/ and (8) (12) synthesized by esterification of the hydroxy-compounds with the appropriate phosphonyl chloride. Treatment of 7r-allyl-palladium chloride with the phosphite ester (13) gave a complex that was an enantioselective catalyst for hydrogenation of unsaturated acids and esters. ... 

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