This thesis will describe the development of a new route to homoallylic amines 9, in four steps from alcohols 1, or acetals 2, which may themselves have to be synthesised. The synthesis is stereoselective, and generates <i>E</i>-9 and <i>Z</i>-9 quite separately, thereby avoiding the sometimes difficult separation of these isomers. Alkenes 3, readily available from alcohols 1 or acetals 2, undergo regio- and stereo-selective 1,3-dipolar cycloadditions with nitrile oxides 4 or nitrones 6. The resulting heterocycles 5 and 7 are reductively cleaved to give β-hydroxy-δ-aminoalkyldiphenylphosphine oxides 8. These alcohols undergo Horner-Emmons-type elimination of sodium diphenylphosphinite to give homallylic amines 9, stereospecifically. Isoxazolines 5, resulting from nitrile oxide cycloadditions, undergo stereoselective reduction, and give rise to primary amines 9, R<SUP>3 =</SUP> H. Isoxazolines 7, resulting from nitrone cycloadditions, give rise to secondary amines 9, R<SUP>3 =</SUP> alkyl or aryl. When the alkoxy substituted alkenes 3, R<SUP>1 =</SUP> OR are used, protected enol ethers 9, R<SUP>1 =</SUP> OR, R<SUP>3 =</SUP> Ac are the final products. The vital cycloaddition and reduction steps are both high yielding, although the elimination is often less so.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:596156 |
| Date | January 1992 |
| Creators | Armstrong, S. K. |
| Publisher | University of Cambridge |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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