Kinetic Influences on Enantioselectivity for Non-Diastereopure Catalyst Mixtures.

Different kinetic rate laws were observed for two diastereomeric catalysts which separately gave opposite enantioselectivities in the asymmetric hydrogenation of the dimethyl ester of itaconic acid. In reactions carried out using an equal mixture of the two catalysts, a conversion-dependent enantioselectivity was predicted from the separate reaction-rate data, in agreement with the experimentally observed final enantioselectivity of 54.8 % ee (see diagram).