Nitrogen-directed free radical rearrangements
<p>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).</p&g...
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| Format: | Thesis |
| Language: | English |
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2002
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| _version_ | 1817932628132626432 |
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| author | Bebbington, M Bebbington, M. W. P. |
| author2 | Hodgson, D |
| author_facet | Hodgson, D Bebbington, M Bebbington, M. W. P. |
| author_sort | Bebbington, M |
| collection | OXFORD |
| description | <p>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).</p> <p>[illustration in text ...]</p> <p>Scheme a. 1 Nitrogen-directed homoallylic radical rearrangement <em>via</em> intermolecular radical addition.</p> <p>A conceptually novel and theoretically interesting nitrogen-directed neophyl rearrangement (Scheme a.2) was developed into a synthesis of 2- azabenzonorbornanes 2.</p> <p>[illustration in text ...]</p> <p>Scheme a.2 Nitrogen-directed neophyl-like rearrangement to 2-azabenzonorbornanes.</p> <p>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.</p> <p>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.</p> <p>The kinetics and mechanism of these processes are examined where appropriate, leading to estimates of rate constants for the rearrangements.</p> |
| first_indexed | 2024-03-06T20:32:13Z |
| format | Thesis |
| id | oxford-uuid:316d2379-4019-4361-937d-ff1e064f8bb9 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-12-09T03:40:56Z |
| publishDate | 2002 |
| record_format | dspace |
| spelling | oxford-uuid:316d2379-4019-4361-937d-ff1e064f8bb92024-12-07T11:57:16ZNitrogen-directed free radical rearrangementsThesishttp://purl.org/coar/resource_type/c_db06uuid:316d2379-4019-4361-937d-ff1e064f8bb9Bicyclic compoundsFree radical reactionsEnglishPolonsky Theses Digitisation Project2002Bebbington, MBebbington, M. W. P.Hodgson, DHodgson, D<p>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).</p> <p>[illustration in text ...]</p> <p>Scheme a. 1 Nitrogen-directed homoallylic radical rearrangement <em>via</em> intermolecular radical addition.</p> <p>A conceptually novel and theoretically interesting nitrogen-directed neophyl rearrangement (Scheme a.2) was developed into a synthesis of 2- azabenzonorbornanes 2.</p> <p>[illustration in text ...]</p> <p>Scheme a.2 Nitrogen-directed neophyl-like rearrangement to 2-azabenzonorbornanes.</p> <p>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.</p> <p>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.</p> <p>The kinetics and mechanism of these processes are examined where appropriate, leading to estimates of rate constants for the rearrangements.</p> |
| spellingShingle | Bicyclic compounds Free radical reactions Bebbington, M Bebbington, M. W. P. Nitrogen-directed free radical rearrangements |
| title | 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_short | Nitrogen-directed free radical rearrangements |
| title_sort | nitrogen directed free radical rearrangements |
| topic | Bicyclic compounds Free radical reactions |
| work_keys_str_mv | AT bebbingtonm nitrogendirectedfreeradicalrearrangements AT bebbingtonmwp nitrogendirectedfreeradicalrearrangements |