Development and Studies of the Processes Involved in Minor Enantiomer Recycling
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
This thesis describes the development and rationalization of processes involved in a new methodology developed in our group, minor enantiomer recycling.
The first part of the thesis addresses mechanistic studies of one of the reactions involved in minor enantiomer recycling, dual Lewis acid-Lewis base catalyzed acetylcyanation of aldehydes. The methodology uses a combination of a chiral titanium-salen complex with a tertiary amine as a catalytic system in the enantioselective synthesis of O-acylated cyanohydrins from aldehydes and ketonitriles. Mechanistic investigations revealed that the rate-determining step in the reaction changes, depending on the nature of the aldehyde that was used. It was also concluded that cyanohydrin is coordinated to the Lewis acid in the acylation step.
The second part of the thesis deals with minor enantiomer recycling, a highly selective one-pot recycling system. In a first step the product is formed as a minor and a major enantiomer by asymmetric catalysis. Recycling of the minor enantiomer, by selective kinetic resolution, regenerates the starting material. Continuous addition of a second reagent, also involved in a coupled exergonic process, leads to an increase of both yield and enantiomeric excess. Recycling procedures for the synthesis of O-acylated and O-formylated cyanohydrins have been developed with high yield and high enantiomeric excess of the products. The study includes development of the systems, comparison to other methodologies in asymmetric catalysis, and attempts to understand the processes involved.
Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2014. , 66 p.
TRITA-CHE-Report, ISSN 1654-1081 ; 2014:53
asymmetric catalysis, biocatalysis, cyanohydrins, dual activation, Lewis acid, Lewis base, minor enantiomer recycling, recycling, titanium
Research subject Chemistry
IdentifiersURN: urn:nbn:se:kth:diva-156635ISBN: 978-91-7595-338-0OAI: oai:DiVA.org:kth-156635DiVA: diva2:767663
2014-12-18, F3, Lindstedtsvägen 26, KTH, Stockholm, 13:00 (English)
Jørgensen, Karl Anker, Professor
Moberg, Christina, Professor
QC 201412022014-12-022014-12-012014-12-02Bibliographically approved
List of papers