The asymmetric reduction of the prochiral carbonyl group of 6-keto acids attracts interest because it is a key step for the facile synthesis of optically active &lactones. The asymmetric reduction of prochiral ketones has been studied extensively,'and considerable success has been attained especially for aromatic or a, &unsaturated ketones with high optical yields of more than 90% ee. 2 In contrast, aliphatic ketones have generally been reduced with ...
