Promiscuous Substrate-Binding Explains the Enzymatic Stereo- and Regiocontrolled Synthesis of Enantiopure Hydroxy Ketones and Diols

Regioand stereoselective reductions of several diketones to afford enantiopure hydroxy ketones or diols were accomplished using isolated alcohol dehydrogenases (ADHs). Results could be rationalised taking into account different (promiscuous) substrate-binding modes in the active site of the enzyme. Furthermore, interesting natural cyclic diketones were also reduced with high regioand stereoselectivity. Some of the 1,2and 1,3-diketones used in this study were reduced employing a low excess of the hydrogen donor (2propanol) due to the quasi-irreversibility of these ADHcatalysed processes. Thus, using less quantity of cosubstrate, scale-up could be easily achieved.