Throughout all chemical sectors, from lubricants to agrochemicals, ether linkages are important motifs in a broad range of chemical entities. Safety issues and environmental concerns associated with common etherification methods render these methodologies undesirable for large scale applications. We have examined the reductive etherification approach, whereby a carbonyl compound is condensed with an alcohol to afford an enol ether intermediate, which is reduced by hydrogen gas and a heterogeneous platinum catalyst to the corresponding ether product in an overall, atom efficient process. In this work, a thorough interrogation of the reductive etherification reaction conditions with regards to the reaction catalyst, solvent, pH and the specific stoichiometries of these components. This investigation resulted in an improved set of mild conditions utilising a commercially available catalyst and readily available additives. The developed methodology allows access to a range of ethers, including aromatic-containing products, whilst addressing safety and environmental considerations related to all components of the reaction system. A homogeneous iridium catalyst was also investigated for ether bond formation of allylic alcohol substrates. This catalyst, containing an N-heterocyclic carbene and bulky phosphine ligand, is shown to mediate the condensation of allylic alcohols with other alcohol nucleophiles to form a wide array of ether substrates. Further study of this reaction was performed through design of experiment statistical analysis to provide an efficient manifold with low catalyst and nucleophile loadings.
Date of Award | 28 Oct 2021 |
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Original language | English |
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Awarding Institution | - University Of Strathclyde
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Sponsors | University of Strathclyde |
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Supervisor | William Kerr (Supervisor) & David Lindsay (Supervisor) |
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