Asymmetric Synthesis of Optically Pure Pharmacologically Relevant Amines Employing ω‐Transaminases

Various ω‐transaminases were tested for the synthesis of enantiomerically pure amines from the corresponding ketones employing D ‐ or L ‐alanine as amino donor and lactate dehydrogenase to remove the side‐product pyruvate to shift the unfavourable reaction equilibrium to the product side. Both enantiomers, ( R )‐ and ( S )‐amines, could be prepared with up to 99% ee and >99% conversions within 24 h at 50 mM substrate concentration. The activity and stereoselectivity of the amination reaction depended on the ω‐transaminase and substrate employed; furthermore the co‐solvent significantly influenced both the stereoselectivity and activity of the transaminases. Best results were obtained by employing ATA‐117 to obtain the ( R )‐enantiomer and ATA‐113 or ATA‐103 to access the ( S )‐enantiomer with 15% v v −1 DMSO.