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 Na2CO3 in organic media under mild conditions. The reaction parameters solvent effect, amount of lipase, and Na2CO3 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 NEt3. 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.
Herein, we report for the first time the preparation of enantiomerically pure forms of 2,3dihydrobenzofuran-3-ol (1), chroman-4-ol (2), thiochroman-4-ol (3), 1-(furan-2-yl) ethanol ( 5) and 1-(thiophen-2-yl) ethanol (6), using kinetic resolution via CAL-B / Na 2 CO 3 hydrolysis in organic media. The (R)-furnished alcohols and the (S)-remained acetates are recovered enantiopures (ee>99%, E>>200, Conv=50%). Those ideal EKRs are well incorporated to the Mitsunobu inversion protocol in a one pot procedure to give (S)-heterocyclic acetates (1a-3a) in good to excellent enantiomeric excess 88%80%) allowing to overcome the maximum of 50% yield which could be usually reached in a regular KR-processes. To date, the enzymatic resolution of 2,3-dihydrobenzofuran-3-ol (1) and their acetate is rarely described.
Herein, we report for the first time, the high regio- and enantioselective ring opening of a biobased itaconic anhydride catalyzed by the Pseudomonas cepacia lipase (PCL) in tert-butylmethylether (TBME) at...
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