Rhodium Rh COD

As previously stated, Knowles et al. have developed an efficient asymmetric catalyst based on the chiral bisphosphine, A,A-DIPAMP (2), that has chirality at the phosphorus atoms and can form a 5-membered chelate ring with rhodium. [Rh(COD)(A,A-DIPAMP)]+BF4 (13) has been used by Monsanto for the production of l-DOPA (12), a drug used for the treatment of Parkinson s disease, by an asymmetric reduction of the Z-enamide, 14a, in 96% ee (Scheme 1). The pure isomer of the protected amino acid intermediate, 15a, can be obtained upon crystallization from the reaction mixture as it is a conglomerate [15]. 

Miyaura also [50] reported rhodium-catalyzed additions of arylboronic acids to aldimines. Despite the potential production of water from boronic adds by cydic trimerization, no hydrolysis of N-sulfonyl aldimines was observed when boronic acids were used in the rhodium-catalyzed addition to aldimines in anhydrous diox-ane. The reactions proceeded well, regardless of the presence of both an electron-withdrawing and an electron-donating group on the aldehyde or the arylboronic add. For example, the reaction of N-sulfonyl aldimine 79a with boronic acid 2o catalyzed by cationic rhodium [Rh(cod) MeCN)2]BF4 gave 87% yield of the product 80ao, and... 

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