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

• Published in: Chirality
• Main Authors: Braia, Nabila, Merabet‐Khelassi, Mounia, Aribi‐Zouioueche, Louisa
• Other Authors: Algerian Ministry of Higher Education and Scientific Research (MESRS, FNR 2000)
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2018
• Subjects: Antarc*; Antarctica
• 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

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.