Hydrogenation of unsaturated acids and esters

Catalyst S/C ratio Reaction conditions Percent ee of product (confign.) References 

In contrast to the many successful examples for hydrogenation of the parent itaconic acid or its dimethyl ester, only a few ligands have been reported to be efficient for the hydrogenation of / -substituted itaconic acid derivatives. Rh complexes with chiral ligands such as MOD-DIOP,69,69a 69h BPPM,246 Et-DuPhos,247 and TangPhos116 are 

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Enantioselective Hydrogenation of Unsaturated Acid and Ester Derivatives... 

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

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

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

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. ... 

Hydrogenation of unsaturated acids and their methyl esters... 

Hydrogenation of various unsaturated acids and esters catalysed by 1% Pd/Si02 and 10 bar pressure and 293 K... 

Unsaturated acids and esters including fatty acids derivatives are also selectively hydrogenated over homogeneous catalysts , e.g., Ir(CO)Cl(PPh3)2 catalyzes the hydrogenation of styrene, ethylacrylate at 10 Pa and 80-120°C . ... 

Two ruthenium complexes, binap 3.43-Ru(OCOR)2(R = Me,CF3) [892] and binap 3.43-RuX2 (X = Cl, Br, I) [893, 894], are quite useful. The acetate and trifluoroacetate complexes of 3.43 induce selective asymmetric hydrogenations of classes of prochiral olefins that are poorly selective with rhodium complexes. These classes include a,(3- or fcy-unsaturated acids and esters, ally alcohols, j3-acylaminoacrylates and enamide precursors of isoquinoline alkaloids [752, 853, 859, 881, 883, 895]. 

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