Greener methodology for the synthesis of alpha-diazocarbonyl compounds and a novel approach to dioxinone derivatives

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dc.contributor.advisor Collins, Stuart G. en O'Brien, Claire 2016-10-26T11:19:24Z 2016 2016
dc.identifier.citation O'Brien, C. 2016. Greener methodology for the synthesis of alpha-diazocarbonyl compounds and a novel approach to dioxinone derivatives. PhD Thesis, University College Cork. en
dc.identifier.endpage 372 en
dc.description.abstract This thesis outlines a more environmentally benign approach to diazo transfer, and the investigation of the reactivity of -diazocarbonyl compounds when subjected to transition metal and lanthanide catalysis. Extensive studies were carried out to find the optimum conditions for a greener diazo transfer methodology, and this was also applied to a continuous process for the synthesis of -diazo--ketoesters. The first chapter includes a literature review of the synthesis and subsequent reactivity of -diazocarbonyl compounds. An overview of the applications of flow chemistry for the synthesis of hazardous intermediates is also included. The applications of lanthanide catalysts in organic synthesis is also discussed. The second chapter outlines the extensive studies undertaken to determine the optimum conditions for a greener diazo transfer methodology, including base and solvent studies. Use of water as a viable solvent for diazo transfer was successfully investigated. Diazo transfer to a range of -diazo--ketoesters was achieved using 5 mol% triethylamine or DMAP in water with high conversions. Polystyrene-supported benzenesulfonyl azide as an alternative diazo transfer reagent was also explored, as well as investigations into cheaper generation of this safer reagent. This polymer-supported benzenesulfonyl azide was used with 25 mol% of base in water to achieve successful diazo transfer to a range of -diazo--ketoesters. The third chapter describes the application of the new methodology developed in Chapter 2 to a continuous processing approach. Various excellent conditions were identified for both batch and flow reactions. A series of -diazo--ketoesters were synthesised with excellent conversions using 25 mol% triethylamine in 90:10 acetone water using flow chemistry. Successful diazo transfer was also achieved using a polymer-supported benzenesulfonyl azide in water under flow conditions. The fourth chapter discusses the reactivity of -diazo--ketoesters under transition metal and lanthanide catalysis. This chapter describes the synthesis of a range of -ketoesters via transesterification, which were used to synthesise a range of novel -diazo--ketoesters that were used in subsequent decomposition reactions. A novel route to dioxinones via rhodium(II) catalysis is reported. Attempted OH and SH insertion reactions in the presence of various lanthanide(II) catalysts are outlined, leading to some unexpected and interesting rearrangement products. The experimental details, including spectroscopic and analytical data for all compounds prepared, are reported at the end of each chapter. en
dc.format.mimetype application/pdf en
dc.language English en
dc.language.iso en en
dc.publisher University College Cork en
dc.rights © 2016, Claire O'Brien. en
dc.rights.uri en
dc.subject Diazo en
dc.subject Green chemistry en
dc.subject Flow chemistry en
dc.title Greener methodology for the synthesis of alpha-diazocarbonyl compounds and a novel approach to dioxinone derivatives en
dc.type Doctoral thesis en
dc.type.qualificationlevel Doctoral en
dc.type.qualificationname PhD (Science) en
dc.internal.availability Full text not available en Restricted to everyone for five years en 2021-10-25T11:19:24Z
dc.description.version Accepted Version
dc.contributor.funder Irish Research Council for Science, Engineering and Technology en
dc.contributor.funder GlaxoSmithKline en
dc.description.status Not peer reviewed en Analytical and Biological Chemistry Research Facility en Chemistry en
dc.check.reason This thesis is due for publication or the author is actively seeking to publish this material en
dc.check.opt-out No en
dc.thesis.opt-out false
dc.check.entireThesis Entire Thesis Restricted
dc.check.embargoformat Both hard copy thesis and e-thesis en
dc.internal.conferring Autumn 2016 en

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© 2016, Claire O'Brien. Except where otherwise noted, this item's license is described as © 2016, Claire O'Brien.
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