Use this URL to cite or link to this record in EThOS: | https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.559794 |
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Title: | The Aza-Bohlmann cyclisation and the synthesis of Pandanus alkaloids | ||||||
Author: | Macnaughton, Sarah |
ISNI:
0000 0004 2728 148X
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Awarding Body: | University of Oxford | ||||||
Current Institution: | University of Oxford | ||||||
Date of Award: | 2011 | ||||||
Availability of Full Text: |
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Abstract: | |||||||
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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Supervisor: | Robertson, Jeremy ; Dallimore, Jonathan | Sponsor: | Not available | ||||
Qualification Name: | Thesis (Ph.D.) | Qualification Level: | Doctoral | ||||
EThOS ID: | uk.bl.ethos.559794 | DOI: | Not available | ||||
Keywords: | Natural products ; Organic synthesis ; Organic chemistry ; Heterocyclic chemistry ; Furan ; spiroaminal ; spiroaminoacetal ; oxidative spirocyclisation | ||||||
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