Thesis
The Aza-Bohlmann cyclisation and the synthesis of Pandanus alkaloids
- Abstract:
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Bohlmann et al. reported the oxidative spirocyclisation of 2-(ω-hydroxyalkyl)furans under Clauson-Kaas conditions to furnish 1,6-dioxaspiro[4.5]dec-3-enes, thereafter termed the “Bohlmann cyclisation.” This thesis describes the development of an analogous aza-Bohlmann cyclisation. Treatment of 2-(ω-aminoalkyl)furans with m-CPBA or singlet oxygen generates hydroxy- or methoxybutenolides, respectively, which undergo spirocyclisation upon treatment with H₂SO₄ to generate [4.4]- and [4.5]-spiroaminoacetals.
The axial/equatorial preferences of N-sulfonylspiroaminoacetals featuring a 3-O-isovaleryl or 3-O-benzyl substituent are described. Acid-catalysed equilibration revealed that in acetonitrile the axial isomer is thermodynamically favoured for both substrates.
The first total synthesis of the spiroaminoacetal alkaloid pandamarilactone-1 is discussed, via an aza-Bohlmann cyclisation, in 13 steps and 3% overall yield from 4-pentyn-1-ol.
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(Preview, pdf, 1.7MB, Terms of use)
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Authors
- Publication date:
- 2011
- DOI:
- Type of award:
- DPhil
- Level of award:
- Doctoral
- Awarding institution:
- University of Oxford
- Language:
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English
- Keywords:
- Subjects:
- UUID:
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uuid:2c91155f-0c0d-47b4-b8dc-f5e32fb2a8f9
- Local pid:
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ora:6586
- Deposit date:
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2012-11-30
- ARK identifier:
Terms of use
- Copyright holder:
- Sarah Macnaughton
- Copyright date:
- 2012
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