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Integration of racemisation for the CHMO catalysed synthesis of optically pure lactones

Stones, Rachel S; (2000) Integration of racemisation for the CHMO catalysed synthesis of optically pure lactones. Doctoral thesis (Ph.D), UCL (University College London). Green open access

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Traditional chemical procedures can be difficult to perform stereoselectively. Many reactions result in racemic products which require resolution and therefore a maximum of fifty percent product yield - to produce a single enantiomer. The temperature, pressure and reagents involved in many of these reactions make the scale-up of the process from bench to production scale difficult. Biotransformations can offer an alternative route to optically pure products from racemic starting materials, although they often suffer from low yields. The combination of a bioconversion and chemical racemisation could produce a step increase in the yield of enantiomencally pure products. This idea was explored within the research detailed in the thesis. A representative system in which a bioconversion and racemisation step can be combined to produce material with high enantiomeric excess and improved yield was chosen. The Baeyer-Villiger reaction involves the conversion of ketones (or cyclic ketones) to esters (or lactones). The reaction can be catalysed by the monooxygenase group of certain enzymes. The cyclohexanone monooxygenase (CHMO) catalysed bioconversion of a 2-substituted cyclic ketone was used as a model reaction for the combined process. The integrated process was compared with the traditional chemical procedure and the increasingly popular biotransformation. The integrated process was performed in two different type of reactor, a linked reactor and a membrane bioreactor. The process in the linked reactor was found to have no advantage over the chemical or biovconversion process, whilst the process performed in the membrane bioreactor had a significant advantage (in terms of yield and enantiomeric excess) over the chemical and bioconversion route.

Type: Thesis (Doctoral)
Qualification: Ph.D
Title: Integration of racemisation for the CHMO catalysed synthesis of optically pure lactones
Open access status: An open access version is available from UCL Discovery
Language: English
Additional information: Thesis digitised by ProQuest.
Keywords: Pure sciences; Applied sciences; Baeyer-Villiger reaction
URI: https://discovery.ucl.ac.uk/id/eprint/10099095
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