Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.512253
Title: Novel transition metal-catalysed syntheses of carboxylic acid derivatives
Author: Owston, Nathan Ashley
ISNI:       0000 0001 3462 1129
Awarding Body: University of Bath
Current Institution: University of Bath
Date of Award: 2008
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Abstract:
This thesis describes the chemistry developed during a study of novel transition metalcatalysed reactions for the synthesis of carboxylic acid derivatives. Chapter 2 describes a novel protocol for the synthesis of primary amides from alcohols in one-pot where a metal complex mediates two fundamentally different catalytic processes. An iridium catalyst has been shown to be effective for the selective rearrangement of aldoximes into primary amides. In addition, an iridium-catalysed oxidation of activated alcohols via hydrogen transfer has been developed using an alkene as formal oxidant. These reactions have been combined in a sequential process affording good yields for a range of benzylic alcohols. An improved system for the rearrangement of aldoximes into amides using a new ruthenium catalyst is described in Chapter 3. Through a systematic program of optimisation excellent selectivity was achieved for a wide range of substrates at markedly reduced catalyst loading. Chapter 4 describes the development of a ruthenium-catalysed elimination reaction for the conversion of oxime ethers into nitriles. The application of this reaction to tandem and sequential reactions has been explored, albeit with limited success. Also, a method for the ruthenium-catalysed oxidation of alcohols using an electron-deficient alkene as hydrogen acceptor is described, and its application to a tandem oxidation process with a nitrogen nucleophile demonstrated. As an extension of the concept presented in Chapter 4, tandem oxidation processes with oxygen nucleophiles are the subject of Chapter 5. This strategy has been used for the oxidation of primary alcohols to their corresponding methyl esters in one-pot, with good yields obtained for a range of substrates. The use of water as a nucleophile in such a process has also been examined.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.512253  DOI: Not available
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