Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492033
Title: Use of chemo and bio catalysts to form and functionalise cis-dihydrodiols
Author: Berberian, Maria Victoria
Awarding Body: Queen's University Belfast
Current Institution: Queen's University Belfast
Date of Award: 2009
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Abstract:
Arene cis-dihydrodiols are compounds produced exclusively during the bacterial oxidation of aromatic substrates through the action of highly stereo- and regio-specific dioxygenase enzymes. cis-Dihydrodiols are important starting materials in the synthesis of valuable stereoisomeric molecules, which in recent years have attracted the attention of research groups in industry and academia. . The major objective of the present thesis was to investigate the formation and functionalisation of cis-dihydrodiols using chemo- and bio-catalytic methods. Oxidation and reduction reactions of cis-dihydrodiols constitute a common'factor across the project since they lead to the formation of the corresponding catechols and the partially (cyclohexene-) or . fUlly hydrogenated (cyclohexane-) cis-diols. Special attention was paid to methodological developments, the type of catalyst used and the comparison between different synthetic procedures in terms of efficiency, selectivity, sustainability and potential scalability. In general, the resulting products are valuable precursors with application in a variety of industrial processes. Two methods are presented for the production of 3-substitued catechols. In both cases the first synthetic stage involved the bio-catalyzed oxidation of a monosubtituted benzene to the corresponding cis-dihydrodiol, using a toluene dioxygenase enzyme present in Pseudomonas putida UV4 or in Escherichi.a coli DH5(pCLtdo). SUbsequently, two different dehydrogenation routes were taken to convert the cis-dihydrodiol to the corresponding catechol, using either a heterogeneous catalyst (Pd/AC) or a cis-diol dehydrogenase enzyme (NDDR or BDD) present in a recombinant E. coli strain. The performance and potential capability of NDDR and BDD for other dehydrogenation reactions were investigated, including kinetic resolution and catalytic asymmetric synthesis of enantiopure arene cis-dihydrodiols, catechols, ketoalcohols and alkene cis-diols. The synthesized catechols were used as starting compounds for reactions involving the hydroxyl and the substituent groups, as well as ringcleavage reactions. Furthermore, a mild and reliable procedure for the partial and total hydrogenation of 3-substituted benzene cis-dihydrodiols using Rh/G was developed.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.492033  DOI: Not available
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