Enamides homogeneous catalysis

Knowles and co-workers reported that DiPAMP, the most well-known P-stereogenic phosphine, gave 12 with an outstanding (at that time) 96% ee. With this phosphine many other enamides, enol esters and similar compounds could be hydrogenated in high ee. This work can be considered a milestone in the field of enantioselective homogeneous catalysis and have been profusely cited. William S. Knowles was awarded (along with Ryoji Noyori and Barry Sharpless) the Nobel Prize in Chemistry for the year 2001 for his contributions to enantioselective catalysis. ... 

An important milestone in the history of asymmetric homogeneous catalysis was the development of asymmetric homogeneous hydrogenation catalysts based on rhodium complexes with chiral phosphine ligands. Scientists at Monsanto, over a period of years, developed catalysts for the production on an industrial scale of L-Dopa [31-33]. The key step is the asymmetric hydrogenation of an enamide (Scheme 7.6). 

A crucial achievement significantly stimulated the development of the investigation in the field of homogeneous enantioselective catalysis. The Knowles group established a method for the industrial synthesis of I-DOPA, a drug used for the treatment of Parkinson s disease. The key step of the process is the enantiomeric hydrogenation of a prochiral enamide, and this reaction is efficiently catalyzed by the air-stable rhodium complex [Rh(COD)((PP)-CAMP)2]BF4 (Scheme 1.12). 

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