Abstract: Enantiomeric excesses of 95-96% are obtained by the asymmetric hydrogenation of a-acylaminoacrylic acids. The olefin configuration, whether E or Z, has a profound influence on the rate and stereospecificity. Excellent selectivity (-90% ee) was obtained with an a-enol ester, which is the first outstanding result with a nonamide substrate. A catalyst picture is presented and the stereochemical results are discussed.