Nitrogen-directed free radical rearrangements
This thesis describes efforts to develop new methods for the synthesis of bridged azacycles using nitrogen-directed free radical rearrangements. Free radical addition to 7-azanorbornadienes were carried out to give 7-substituted 2- azanorbornenes (Scheme a.l, X-Y = RS-H or PhSe-H). [illustration in...
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ndltd-bl.uk-oai-ethos.bl.uk-2702472015-03-19T05:19:06ZNitrogen-directed free radical rearrangementsBebbington, Magnus W. P.Hodgson, David M.2002This thesis describes efforts to develop new methods for the synthesis of bridged azacycles using nitrogen-directed free radical rearrangements. Free radical addition to 7-azanorbornadienes were carried out to give 7-substituted 2- azanorbornenes (Scheme a.l, X-Y = RS-H or PhSe-H). [illustration in text ...] Scheme a. 1 Nitrogen-directed homoallylic radical rearrangement via intermolecular radical addition. A conceptually novel and theoretically interesting nitrogen-directed neophyl rearrangement (Scheme a.2) was developed into a synthesis of 2- azabenzonorbornanes 2. [illustration in text ...] Scheme a.2 Nitrogen-directed neophyl-like rearrangement to 2-azabenzonorbornanes. In this case the radical 1 was generated by Barton deoxygenation of 7- azabenzonorbornanols. The effect on rearrangement of bicyclic core substitution and of aromatic ring electronics was probed in some detail, and the process was synthetically useful for a wide range of substrates. Variation of the protecting group on nitrogen was investigated and the product profiles from neophyl-like rearrangement were consistent with a process driven by the stability of a radical α to nitrogen as a result of SOMO-lone pair orbital interaction. The kinetics and mechanism of these processes are examined where appropriate, leading to estimates of rate constants for the rearrangements.546Free radical reactions : Bicyclic compoundsUniversity of Oxfordhttp://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270247http://ora.ox.ac.uk/objects/uuid:316d2379-4019-4361-937d-ff1e064f8bb9Electronic Thesis or Dissertation |
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546 Free radical reactions : Bicyclic compounds |
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546 Free radical reactions : Bicyclic compounds Bebbington, Magnus W. P. Nitrogen-directed free radical rearrangements |
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This thesis describes efforts to develop new methods for the synthesis of bridged azacycles using nitrogen-directed free radical rearrangements. Free radical addition to 7-azanorbornadienes were carried out to give 7-substituted 2- azanorbornenes (Scheme a.l, X-Y = RS-H or PhSe-H). [illustration in text ...] Scheme a. 1 Nitrogen-directed homoallylic radical rearrangement via intermolecular radical addition. A conceptually novel and theoretically interesting nitrogen-directed neophyl rearrangement (Scheme a.2) was developed into a synthesis of 2- azabenzonorbornanes 2. [illustration in text ...] Scheme a.2 Nitrogen-directed neophyl-like rearrangement to 2-azabenzonorbornanes. In this case the radical 1 was generated by Barton deoxygenation of 7- azabenzonorbornanols. The effect on rearrangement of bicyclic core substitution and of aromatic ring electronics was probed in some detail, and the process was synthetically useful for a wide range of substrates. Variation of the protecting group on nitrogen was investigated and the product profiles from neophyl-like rearrangement were consistent with a process driven by the stability of a radical α to nitrogen as a result of SOMO-lone pair orbital interaction. The kinetics and mechanism of these processes are examined where appropriate, leading to estimates of rate constants for the rearrangements. |
author2 |
Hodgson, David M. |
author_facet |
Hodgson, David M. Bebbington, Magnus W. P. |
author |
Bebbington, Magnus W. P. |
author_sort |
Bebbington, Magnus W. P. |
title |
Nitrogen-directed free radical rearrangements |
title_short |
Nitrogen-directed free radical rearrangements |
title_full |
Nitrogen-directed free radical rearrangements |
title_fullStr |
Nitrogen-directed free radical rearrangements |
title_full_unstemmed |
Nitrogen-directed free radical rearrangements |
title_sort |
nitrogen-directed free radical rearrangements |
publisher |
University of Oxford |
publishDate |
2002 |
url |
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270247 |
work_keys_str_mv |
AT bebbingtonmagnuswp nitrogendirectedfreeradicalrearrangements |
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1716740898070462464 |