Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.659789
Title: Development of catalytic stereoselective aldol cyclisations
Author: Murray, Gordon John
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 2008
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Abstract:
The development of a diastereoselective reductive aldol reaction and its application in the synthesis of a number of 4-hydroxypiperidin-2-ones are described. The reactions proceed in the presence of Cu(OAc)2.H2O, a bis-phosphine ligand and TMDS (1,1,3,3-tetramethyldisiloxane). The scope of this process with respect to the ketone functionality is broad, encompassing a range of aliphatic, aromatic and heteroaromatic groups. Synthetic applications of the resulting β-hydroxycarbonyl compounds, including the preparation of enantioenriched piperidines, are discussed. The use of chiral non-racemic bis-phosphine ligands enables the lactam products to be isolated in up to 65% ee. The development of a diastereoselective reductive aldol reaction and its application in the synthesis of substituted 4-hydroxypiperidin-2-ones and pyrrolidine-2-ones are described. The reactions proceed in the presence of either Co(acac)2.2H2O or Ni(acac)2 and diethylzinc. The scope of this process with respect to the α,β-unsaturated component is broad, encompassing a range of aliphatic and aromatic groups. Catalyst optimisation studies including the evaluation of a number of chiral, non-racemic ligands are discussed. Catalytic, enantioselective aldol cyclisations of substituted malonic esters tethered to a ketone through an amide linkage are described. The development of an effective catalyst system through the evaluation of Lewis acid catalysts and hydrogen bonding catalysts are discussed. The potential use of the developed methodology to the synthesis of complex natural products is presented.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.659789  DOI: Not available
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