Bonded Bridging Ligands for Self-Supported Catalysts

1 Covalent Bonded Bridging Ligands for Self-Supported Catalysts 

The use of monodentate phosphorus ligands in Rh-catalyzed enantioselective hydrogenation of olefin derivatives represents one of the breakthroughs in the area of asymmetric hydrogenation [62], wherein the generally accepted mechanism 

With 56g as the heterogeneous catalyst, asymmetric hydrogenation of a-dehydroamino acid esters 48b and 48c, enamide 50a, and itaconic acid ester 57 were performed in toluene at room temperature under 40 atm of H2 to afford the corresponding products with full conversion in 90-97% ee, which were comparable or even superior to those obtained with their homogeneous counterpart (MonoPhos)2/Rh(I). Upon completion of the reaction, the catalyst 

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