Chemo- and Enzyme-Catalyzed Reactions Revealing a Common Temperature-Dependent Dynamic Solvent Effect on Enantioselectivity
✍ Scribed by Gianfranco Cainelli; Paola Galletti; Daria Giacomini; Andrea Gualandi; Arianna Quintavalla
- Publisher
- John Wiley and Sons
- Year
- 2003
- Tongue
- German
- Weight
- 202 KB
- Volume
- 86
- Category
- Article
- ISSN
- 0018-019X
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✦ Synopsis
Abstract
The enantiomeric ratio E of enzyme‐catalyzed (Candida antarctica lipase and lipase PS) and chemo‐catalyzed (L‐proline‐based diamines) acylation reactions of 1‐(naphthalen‐2‐yl)ethanol, 2‐phenylpropanol, and 2‐benzylpropane‐1,3‐diol is dependent on solvent and temperature. Plots of ln E vs. 1/T showed the presence of inversion temperatures (T~inv~). The T~inv~ values for the bio‐catalyzed and the chemo‐catalyzed reactions are fairly in agreement, and correspond as well to the T~NMR~ values obtained by variable‐temperature ^13^C‐NMR experiments on the substrates in the same solvent of the resolution. This result demonstrates that clustering effects in the substrate solvation manage the chemical and the enzymatic enantioselectivity, and, moreover, that the solutesolvent cluster is always the real reacting species in solution for chemical as well as for enzymatic reactions.