Dynamic Kinetic Resolution of Secondary Alcohols Combining Enzyme‐Catalyzed Transesterification and Zeolite‐Catalyzed Racemization
Abstract Hydrophobic zeolite beta containing low concentrations of Zr or Al was found to be a good catalyst for the racemization of 1‐phenylethanol. The formation of styrene as a side product could be minimized by reducing the metal concentration in the zeolite beta. Combined with an immobilized lip...
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crwiley:10.1002/chem.200600723 2024-06-02T07:58:29+00:00 Dynamic Kinetic Resolution of Secondary Alcohols Combining Enzyme‐Catalyzed Transesterification and Zeolite‐Catalyzed Racemization Zhu, Yongzhong Fow, Kam‐Loon Chuah, Gaik‐Khuan Jaenicke, Stephan 2006 http://dx.doi.org/10.1002/chem.200600723 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fchem.200600723 https://onlinelibrary.wiley.com/doi/full/10.1002/chem.200600723 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Chemistry – A European Journal volume 13, issue 2, page 541-547 ISSN 0947-6539 1521-3765 journal-article 2006 crwiley https://doi.org/10.1002/chem.200600723 2024-05-03T11:13:35Z Abstract Hydrophobic zeolite beta containing low concentrations of Zr or Al was found to be a good catalyst for the racemization of 1‐phenylethanol. The formation of styrene as a side product could be minimized by reducing the metal concentration in the zeolite beta. Combined with an immobilized lipase from Candida antarctica , the dynamic kinetic resolution of 1‐phenylethanol to the ( R )‐phenylethylester can be achieved with high yield and selectivity. The reaction was best conducted in toluene as solvent at 60 °C, with higher temperatures leading to a loss in the enantioselectivity of the formed ester. By using high‐molecular‐weight acyl‐transfer reagents, such as vinyl butyrate or vinyl octanoate, a high enantiomeric excess of the product esters of 92 and 98 %, respectively, could be achieved. This is attributed to a steric effect: the bulky ester is less able to enter the pore space of the zeolite catalyst where the active sites for racemization are localized. Close to 100 % conversion of the alcohol was achieved within 2 h. If the more common acyl donor, isopropenyl acetate, was used, the enantiomeric excess ( ee ) of the formed ester was only 67 %, and the reaction was considerably slower. Article in Journal/Newspaper Antarc* Antarctica Wiley Online Library Chemistry – A European Journal 13 2 541 547 |
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English |
description |
Abstract Hydrophobic zeolite beta containing low concentrations of Zr or Al was found to be a good catalyst for the racemization of 1‐phenylethanol. The formation of styrene as a side product could be minimized by reducing the metal concentration in the zeolite beta. Combined with an immobilized lipase from Candida antarctica , the dynamic kinetic resolution of 1‐phenylethanol to the ( R )‐phenylethylester can be achieved with high yield and selectivity. The reaction was best conducted in toluene as solvent at 60 °C, with higher temperatures leading to a loss in the enantioselectivity of the formed ester. By using high‐molecular‐weight acyl‐transfer reagents, such as vinyl butyrate or vinyl octanoate, a high enantiomeric excess of the product esters of 92 and 98 %, respectively, could be achieved. This is attributed to a steric effect: the bulky ester is less able to enter the pore space of the zeolite catalyst where the active sites for racemization are localized. Close to 100 % conversion of the alcohol was achieved within 2 h. If the more common acyl donor, isopropenyl acetate, was used, the enantiomeric excess ( ee ) of the formed ester was only 67 %, and the reaction was considerably slower. |
format |
Article in Journal/Newspaper |
author |
Zhu, Yongzhong Fow, Kam‐Loon Chuah, Gaik‐Khuan Jaenicke, Stephan |
spellingShingle |
Zhu, Yongzhong Fow, Kam‐Loon Chuah, Gaik‐Khuan Jaenicke, Stephan Dynamic Kinetic Resolution of Secondary Alcohols Combining Enzyme‐Catalyzed Transesterification and Zeolite‐Catalyzed Racemization |
author_facet |
Zhu, Yongzhong Fow, Kam‐Loon Chuah, Gaik‐Khuan Jaenicke, Stephan |
author_sort |
Zhu, Yongzhong |
title |
Dynamic Kinetic Resolution of Secondary Alcohols Combining Enzyme‐Catalyzed Transesterification and Zeolite‐Catalyzed Racemization |
title_short |
Dynamic Kinetic Resolution of Secondary Alcohols Combining Enzyme‐Catalyzed Transesterification and Zeolite‐Catalyzed Racemization |
title_full |
Dynamic Kinetic Resolution of Secondary Alcohols Combining Enzyme‐Catalyzed Transesterification and Zeolite‐Catalyzed Racemization |
title_fullStr |
Dynamic Kinetic Resolution of Secondary Alcohols Combining Enzyme‐Catalyzed Transesterification and Zeolite‐Catalyzed Racemization |
title_full_unstemmed |
Dynamic Kinetic Resolution of Secondary Alcohols Combining Enzyme‐Catalyzed Transesterification and Zeolite‐Catalyzed Racemization |
title_sort |
dynamic kinetic resolution of secondary alcohols combining enzyme‐catalyzed transesterification and zeolite‐catalyzed racemization |
publisher |
Wiley |
publishDate |
2006 |
url |
http://dx.doi.org/10.1002/chem.200600723 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fchem.200600723 https://onlinelibrary.wiley.com/doi/full/10.1002/chem.200600723 |
genre |
Antarc* Antarctica |
genre_facet |
Antarc* Antarctica |
op_source |
Chemistry – A European Journal volume 13, issue 2, page 541-547 ISSN 0947-6539 1521-3765 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1002/chem.200600723 |
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Chemistry – A European Journal |
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13 |
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2 |
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541 |
op_container_end_page |
547 |
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1800741853682728960 |