Stereo‐Complementary Two‐Step Cascades Using a Two‐Enzyme System Leading to Enantiopure Epoxides

A novel one‐pot, two‐step, two‐enzyme cascade is described. Pro‐chiral α‐chloro ketones are stereoselectively reduced to the corresponding halohydrins as an intermediate by a biocatalytic hydrogen transfer process. The intermediate is transformed to the corresponding epoxide by a non‐enantioselective halohydrin dehalogenase. Thus, by combining a Prelog‐ or anti‐Prelog alcohol dehydrogenase with a non‐selective halohydrin dehalogenase, enantiopure ( R )‐ as well as ( S )‐epoxides were obtained.