Ruthenium-catalyzed redox reactions and lipase-catalyzed asymmetric transformations of alcohols
The major part of this thesis describes the synthesis of enantiopure alcohols and diols by combining ruthenium-catalyzed redox reactions that lead to racemization or epimerization and lipase-catalyzed asymmetric trans-formations in one-pot. A mechanistic study of the unexpected facile formation of m...
Main Author: | |
---|---|
Format: | Doctoral or Postdoctoral Thesis |
Language: | English |
Published: |
Stockholms universitet, Institutionen för organisk kemi
2005
|
Subjects: | |
Online Access: | http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-537 |
id |
ftstockholmuniv:oai:DiVA.org:su-537 |
---|---|
record_format |
openpolar |
spelling |
ftstockholmuniv:oai:DiVA.org:su-537 2023-05-15T13:33:25+02:00 Ruthenium-catalyzed redox reactions and lipase-catalyzed asymmetric transformations of alcohols Edin, Michaela 2005 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-537 eng eng Stockholms universitet, Institutionen för organisk kemi Stockholm : Institutionen för organisk kemi http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-537 urn:isbn:91-7155-053-4 info:eu-repo/semantics/openAccess ruthenium lipase catalysis alcohols diols Chemistry Kemi Doctoral thesis, comprehensive summary info:eu-repo/semantics/doctoralThesis text 2005 ftstockholmuniv 2023-02-23T21:38:37Z The major part of this thesis describes the synthesis of enantiopure alcohols and diols by combining ruthenium-catalyzed redox reactions that lead to racemization or epimerization and lipase-catalyzed asymmetric trans-formations in one-pot. A mechanistic study of the unexpected facile formation of meso-diacetate products found in enzyme-catalyzed acetylations of alkanediols with Candida antarctica lipase B (CALB) was first performed. By deuterium labeling it was found that the formation of meso-diacetates proceeds via different mechanisms for 2,4-pentanediol and 2,5-hexanediol. Whereas the first reacts via an intramolecular acyl migration, the latter proceeds via a direct, anomalous S-acylation of the alcohol. The acyl migration occurring in the 2,4-pentanediol monoacetate was taken advantage of in asymmetric transformations of substituted 1,3-diols by combining it with a ruthenium-catalyzed epimerization and an enzymatic transesterification using CALB. The in situ coupling of these three processes results in de-epimerization and deracemization of acyclic, unsymmetrical 1,3-diols and constitutes a novel dynamic kinetic asymmetric transformation (DYKAT) concept. Racemization of secondary alcohols effected by a new ruthenium complex was combined in one-pot with an enzyme-catalyzed transesterification, leading to a chemoenzymatic dynamic kinetic resolution (DKR) operating at room temperature. Aromatic, aliphatic, heterocyclic and functionalized alcohols were subjected to the procedure. A mechanism for racemization by this ruthenium complex has been proposed and experimental indications for hydrogen transfer within the coordination sphere of ruthenium were found. The same ruthenium catalyst was used for epimerization in DYKAT of 1,2-diols, and a very similar complex was employed in isomerization of allylic alcohols to saturated ketones. The former method is a substrate extension of the above principle applied for DYKAT of 1,3-diols. The combination of a lipase and an organocatalyst was demonstrated by linking a ... Doctoral or Postdoctoral Thesis Antarc* Antarctica Stockholm University: Publications (DiVA) |
institution |
Open Polar |
collection |
Stockholm University: Publications (DiVA) |
op_collection_id |
ftstockholmuniv |
language |
English |
topic |
ruthenium lipase catalysis alcohols diols Chemistry Kemi |
spellingShingle |
ruthenium lipase catalysis alcohols diols Chemistry Kemi Edin, Michaela Ruthenium-catalyzed redox reactions and lipase-catalyzed asymmetric transformations of alcohols |
topic_facet |
ruthenium lipase catalysis alcohols diols Chemistry Kemi |
description |
The major part of this thesis describes the synthesis of enantiopure alcohols and diols by combining ruthenium-catalyzed redox reactions that lead to racemization or epimerization and lipase-catalyzed asymmetric trans-formations in one-pot. A mechanistic study of the unexpected facile formation of meso-diacetate products found in enzyme-catalyzed acetylations of alkanediols with Candida antarctica lipase B (CALB) was first performed. By deuterium labeling it was found that the formation of meso-diacetates proceeds via different mechanisms for 2,4-pentanediol and 2,5-hexanediol. Whereas the first reacts via an intramolecular acyl migration, the latter proceeds via a direct, anomalous S-acylation of the alcohol. The acyl migration occurring in the 2,4-pentanediol monoacetate was taken advantage of in asymmetric transformations of substituted 1,3-diols by combining it with a ruthenium-catalyzed epimerization and an enzymatic transesterification using CALB. The in situ coupling of these three processes results in de-epimerization and deracemization of acyclic, unsymmetrical 1,3-diols and constitutes a novel dynamic kinetic asymmetric transformation (DYKAT) concept. Racemization of secondary alcohols effected by a new ruthenium complex was combined in one-pot with an enzyme-catalyzed transesterification, leading to a chemoenzymatic dynamic kinetic resolution (DKR) operating at room temperature. Aromatic, aliphatic, heterocyclic and functionalized alcohols were subjected to the procedure. A mechanism for racemization by this ruthenium complex has been proposed and experimental indications for hydrogen transfer within the coordination sphere of ruthenium were found. The same ruthenium catalyst was used for epimerization in DYKAT of 1,2-diols, and a very similar complex was employed in isomerization of allylic alcohols to saturated ketones. The former method is a substrate extension of the above principle applied for DYKAT of 1,3-diols. The combination of a lipase and an organocatalyst was demonstrated by linking a ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Edin, Michaela |
author_facet |
Edin, Michaela |
author_sort |
Edin, Michaela |
title |
Ruthenium-catalyzed redox reactions and lipase-catalyzed asymmetric transformations of alcohols |
title_short |
Ruthenium-catalyzed redox reactions and lipase-catalyzed asymmetric transformations of alcohols |
title_full |
Ruthenium-catalyzed redox reactions and lipase-catalyzed asymmetric transformations of alcohols |
title_fullStr |
Ruthenium-catalyzed redox reactions and lipase-catalyzed asymmetric transformations of alcohols |
title_full_unstemmed |
Ruthenium-catalyzed redox reactions and lipase-catalyzed asymmetric transformations of alcohols |
title_sort |
ruthenium-catalyzed redox reactions and lipase-catalyzed asymmetric transformations of alcohols |
publisher |
Stockholms universitet, Institutionen för organisk kemi |
publishDate |
2005 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-537 |
genre |
Antarc* Antarctica |
genre_facet |
Antarc* Antarctica |
op_relation |
http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-537 urn:isbn:91-7155-053-4 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1766042078046846976 |