Abstract
The studies on the enantioselective hydrogenation of prochiral olefins with heterogeneous palladium catalysts in these 20 years are briefly reviewed. The experimental results mainly on the hydrogenation of α, β-unsaturated carboxylic acids with cinchona alkaloids-modified Pd catalysts are described from the points of substrate structure, modifier structure, catalyst preparation method, support texture, pretreatments, reaction conditions (e.g., solvent, hydrogen pressure, reaction temperature, additives, etc.), and the reaction mechanism. The highest ee up to81% has been achieved for the reaction of (E) -2, 3-diphenylpropenoic acid, and up to92% for its derivative, (E) -2, 3-di (4-methoxyphenyl) propenoic acid, with a cinchonidine-modified Pd/C catalyst under an optimized reaction condition. More systematic studies for understanding the reaction mechanisms will lead to further improvement of this catalytic system.
