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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
Author(s) -
Braia Nabila,
MerabetKhelassi Mounia,
AribiZouioueche Louisa
Publication year - 2018
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/chir.23025
Subject(s) - chemistry , phenol , hydrolysis , lipase , acylation , regioselectivity , enantiomer , organic chemistry , vinyl acetate , candida antarctica , catalysis , alkaline hydrolysis , enantioselective synthesis , biocatalysis , medicinal chemistry , enzyme , reaction mechanism , polymer , copolymer
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.