Enzymatic In Vitro Reduction of Ketones. Part 111. The Unexpected Steric Course of the HLAD Catalyzed Reduction of 3-Cyanocyclohexanone

3-Cyanocyclohexanone is a suitable substrate for preparative HLAD reduction, delivering enantiomerically pure (1S, 3S)-trans and (1R, 3S)-cis-alcohols. Details are given on the kinetics of the reduction and the absolute configuration of the products. In contrast to recently developed reaction models an important amount of (1R,3S)-cis-alcohol is formed. Some side reactions of the substrate with the TRIS-buffered medium are described.