Deracemization of diastereomerically pure syn- and anti-α-substituted β-hydroxyesters by Novozyme 435 lipase and determination of their absolute configuration by NMR spectroscopy
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Contributors
Abstract
Enantiomerically pure α-substituted β-hydroxyesters are important chiral building blocks for ligands, auxiliaries and β-lactam antibiotics. A two-step chemo-enzymatic procedure using lipase as biocatalyst is an efficient way to synthesize such products. To date, the methods described are limited to molecules that do not contain a chiral center adjacent to the racemic carbinol, and furthermore, they are limited to acylation. Here, we investigated the deracemization of diastereomerically pure syn- and anti-α-substituted β-hydroxyesters containing two stereo centers, using experimental methods under neat conditions and classical molecule dynamics (MD) simulation. A screening of free and immobilized commercial lipases identified immobilized lipase B from Candida antarctica (Novozyme 435) as the most appropriate biocatalyst for sterically demanding α-substituted β-hydroxyesters. Using Novozyme 435, reaction conditions were optimized and hydroxyesters (3S) or (3R) were achieved with enantiomeric excesses up to ≥99% ee and maximum overall yields of 80%. The absolute configuration of the enantiomers was eventually determined by 1H-NMR spectroscopy after derivatization with MOSHER'S reagent (α-methoxy-α-trifluoromethylphenylacetic acid = MTPA).
Details
Original language | English |
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Article number | 111578 |
Journal | Molecular Catalysis |
Volume | 509 |
Publication status | Published - Jun 2021 |
Peer-reviewed | Yes |
Externally published | Yes |
Keywords
ASJC Scopus subject areas
Keywords
- Candida antarctica Lipase B, Catalysis, Enzymatic kinetic resolution, Molecular docking, MOSHER'S reagent, NMR Spectroscopy, Novozyme 435, β-Hydroxyesters