Amide Unsaturated, enantioselective nitrile

Unsaturated Carboxylic Add Amides, Esters, and Nitriles Enantioselective hydroformylation of dialkylacrylamides was investigated by Clarke and coworkers in detail (Scheme 4.81) [56]. It was found that these substrates undergo hydroformylation more slowly than styrene. Up to 82% ee was realized in the best trials. A serious problem was caused by the epimerization of chiral aldehydes by the intermediarily formed umnodified rhodium hydride complexes. Therefore, the reaction times should be kept short, and low temperatures are recommended. 

A wide range of a,P-unsaturated acceptors work well under standard reaction conditions with pre-catalyst 75c (Table 7). Acceptors include a,P-unsaturated esters, amides, alkyl ketones, and phosphine oxides, many of which provide the products in greater than 90% ee [68, 69], a,P-Unsaturated phenyl ketones, nitriles, and thioesters also work, albeit with lower enantioselectivity. The scope has been extended to include a variety of vinyl phosphonate precursors providing good chemical yields and moderate to high enantioselectivity (entries 9 and 10). 

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