Enantioselective Synthesis of Pharmaceutically Active gamma-Aminobutyric Acids Using a Tailor-Made Artificial Michaelase in One-Pot Cascade Reactions.
Biewenga, L., Saravanan, T., Kunzendorf, A., van der Meer, J.Y., Pijning, T., Tepper, P.G., van Merkerk, R., Charnock, S.J., Thunnissen, A.W.H., Poelarends, G.J.(2019) ACS Catal 9: 1503-1513
- PubMed: 30740262 
- DOI: https://doi.org/10.1021/acscatal.8b04299
- Primary Citation of Related Structures:  
6FPS - PubMed Abstract: 
Chiral γ-aminobutyric acid (GABA) analogues represent abundantly prescribed drugs, which are broadly applied as anticonvulsants, as antidepressants, and for the treatment of neuropathic pain. Here we report a one-pot two-step biocatalytic cascade route for synthesis of the pharmaceutically relevant enantiomers of γ-nitrobutyric acids, starting from simple precursors (acetaldehyde and nitroalkenes), using a tailor-made highly enantioselective artificial "Michaelase" (4-oxalocrotonate tautomerase mutant L8Y/M45Y/F50A), an aldehyde dehydrogenase with a broad non-natural substrate scope, and a cofactor recycling system. We also report a three-step chemoenzymatic cascade route for the efficient chemical reduction of enzymatically prepared γ-nitrobutyric acids into GABA analogues in one pot, achieving high enantiopurity (e.r. up to 99:1) and high overall yields (up to 70%). This chemoenzymatic methodology offers a step-economic alternative route to important pharmaceutically active GABA analogues, and highlights the exciting opportunities available for combining chemocatalysts, natural enzymes, and designed artificial biocatalysts in multistep syntheses.
Organizational Affiliation: 
Department of Chemical and Pharmaceutical Biology, Groningen Research Institute of Pharmacy, University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.