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Chemo‐ and Enzyme‐Catalyzed Reactions Revealing a Common Temperature‐Dependent Dynamic Solvent Effect on Enantioselectivity
Author(s) -
Cainelli Gianfranco,
Galletti Paola,
Giacomini Daria,
Gualandi Andrea,
Quintavalla Arianna
Publication year - 2003
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200390299
Subject(s) - chemistry , lipase , kinetic resolution , catalysis , acylation , solvent , candida antarctica , substrate (aquarium) , enzyme catalysis , solvation , enantiomeric excess , solvent effects , enzyme , organic chemistry , enantiomer , racemization , stereochemistry , enantioselective synthesis , oceanography , geology
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.