Efficient access to both enantiomers of 3‐(1‐hydroxyethyl)phenol by regioselective and enantioselective CAL‐B–catalyzed hydrolysis of diacetate in organic media by sodium carbonate
Abstract In the present paper, we describe several pathways employing immobilized lipase from Candida antarctica B ( CAL‐B ) as biocatalyst to prepare easily both enantiomers of 3‐(1‐hydroxyethyl)phenol. We have applied hydrolysis with Na 2 CO 3 in organic media under mild conditions. The reaction p...
Published in: | Chirality |
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Main Authors: | , , |
Other Authors: | |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Wiley
2018
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Subjects: | |
Online Access: | http://dx.doi.org/10.1002/chir.23025 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fchir.23025 https://onlinelibrary.wiley.com/doi/pdf/10.1002/chir.23025 |
Summary: | Abstract In the present paper, we describe several pathways employing immobilized lipase from Candida antarctica B ( CAL‐B ) as biocatalyst to prepare easily both enantiomers of 3‐(1‐hydroxyethyl)phenol. We have applied hydrolysis with Na 2 CO 3 in organic media under mild conditions. The reaction parameters solvent effect, amount of lipase, and Na 2 CO 3 were examined with 3‐(1‐acetoxyethyl)phenyl acetate as substrate. In alkaline hydrolysis, ( R )‐3‐(1‐hydroxyethyl)phenol was obtained with ee = 99% and ( S )‐( − )‐3‐(1‐acetoxyethyl)phenol with ee = 98% at optimal conversion (c = 50%) and high selectivity (E > 200). Two other deacylation reactions were compared: alcoholysis with MeOH and with NEt 3 . The acylation of 3‐(1‐hydroxyethyl)phenol with vinyl acetate was also examined. Alkaline hydrolysis gave the best results, while good regioselectivity and enantioselectivity were observed in alcoholysis and acylation reactions. Finally, ( S )‐ and ( R )‐3‐(1‐hydroxyethyl)phenol (ee > 98%), key intermediates for the synthesis of important drugs, were prepared from the corresponding racemic diacetate through alkaline hydrolysis. |
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