Synthesis and reactivity of pyridine substituted α-diazocarbonyl compounds and exploration of rhodium carboxylates as asymmetric catalysts

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dc.contributor.advisor Maguire, Anita R. en
dc.contributor.author Feerick, Brian
dc.date.accessioned 2015-10-23T09:04:54Z
dc.date.issued 2014
dc.date.submitted 2014
dc.identifier.citation Feerick, B. 2014. Synthesis and reactivity of pyridine substituted alpha-diazocarbonyl compounds and exploration of rhodium carboxylates as asymmetric catalysts. PhD Thesis, University College Cork. en
dc.identifier.endpage 424
dc.identifier.uri http://hdl.handle.net/10468/2005
dc.description.abstract The primary objective of this thesis was the preparation of a series of pyridine-containing α-diazocarbonyl compounds and subsequent investigation of the reactivity of these compounds on exposure to transition metal catalysts. In particular, the reactivity of the pyridyl α-diazocarbonyls was compared to that of the analogous phenyl α-diazocarbonyl compounds to ascertain the impact of replacement of the phenyl ring with pyridine. The first chapter initially provides a brief introduction into α-diazocarbonyl chemistry, comprising a compendium of well-established and recently developed methods in the preparation of these compounds, as well as an outline of the reactivity of these versatile substrates. The substantive element of this introductory chapter comprises a detailed review focused on transition metal-catalysed transformations of heterocyclic α-diazocarbonyl compounds, highlighting the extraordinary diversity of reaction products which can be accessed. This review is undertaken to set the work of this thesis in context. The results of this research are discussed in the second and third chapters together with the associated experimental details, including spectroscopic and analytical data obtained in the synthesis of all compounds during this research. The second chapter describes the preparation of a range of novel pyridine-containing α-diazocarbonyl compounds via a number of synthetic strategies including both acylation and diazo transfer methodologies. In contrast to the phenyl analogues, the generation of the pyridine α-diazocarbonyl substrates was complicated by a number of factors including the inherent basicity of the pyridine ring, tautomerism and existence of rotamers. Rhodium- and copper-mediated transformations of the pyridine-containing α-diazocarbonyl compounds is discussed in detail displaying very different reactivity patterns to those seen with the phenyl analogues; oxidation to 2,3- diketones, 1,2-hydride shift to form enones and oxonium and sulfonium ylide formation/rearrangement are prominent in the pyridyl series, with no evidence of aromatic addition to the pyridine ring. The third chapter focuses on exploration of novel chiral rhodium(II) catalysts, developed in the Maguire team, in both intermolecular cyclopropanations and intramolecular C–H insertion reactions. In this chapter, the studies are focused on standard α-diazocarbonyl compounds without heteroaryl substituents. The most notable outcome was the achievement of high enantiopurities for intramolecular C–H insertions, which were competitive with, and even surpassed, established catalyst systems in some cases. This work has provided insight into solvent and temperature effects on yields as well as enantio- and diastereoselectivity, thereby providing guidance for future development and design of chiral rhodium carboxylate catalysts. While this is a preliminary study, the significance of the results lie in the fact that these are the first reactions to give substantial asymmetric induction with these novel rhodium carboxylates. While the majority of the α-diazocarbonyl compounds explored in this work were α-diazoketones, a number of α-diazoesters are also described. Details of chiral stationary phase HPLC analysis, single crystal analysis and 2D NMR experiments are included in the Appendix (Appendix III-V). en
dc.description.sponsorship Irish Research Council for Science Engineering and Technology (RS/2006/72) en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher University College Cork en
dc.rights © 2014, Brian Feerick. en
dc.rights.uri http://creativecommons.org/licenses/by-nc-nd/3.0/ en
dc.subject Pyridine diazoketones en
dc.subject Pyridine en
dc.subject Diazoketones en
dc.title Synthesis and reactivity of pyridine substituted α-diazocarbonyl compounds and exploration of rhodium carboxylates as asymmetric catalysts en
dc.title.alternative Synthesis and reactivity of pyridine substituted alpha-diazocarbonyl compounds and exploration of rhodium carboxylates as asymmetric catalysts 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
dc.check.info Restricted to everyone for five years en
dc.check.date 2020-10-21T09:04:54Z
dc.description.version Accepted Version
dc.contributor.funder Irish Research Council for Science Engineering and Technology en
dc.description.status Not peer reviewed en
dc.internal.school 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 Not applicable en
dc.thesis.opt-out false
dc.check.entireThesis Entire Thesis Restricted
dc.check.embargoformat Both hard copy thesis and e-thesis en
ucc.workflow.supervisor a.maguire@ucc.ie
dc.internal.conferring Spring Conferring 2015


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