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http://hdl.handle.net/11375/8625
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DC Field | Value | Language |
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dc.contributor.advisor | Warkentin, John | en_US |
dc.contributor.author | Tomaszewski, Jerzy Miroslaw | en_US |
dc.date.accessioned | 2014-06-18T16:43:29Z | - |
dc.date.available | 2014-06-18T16:43:29Z | - |
dc.date.created | 2011-01-11 | en_US |
dc.date.issued | 1992-06 | en_US |
dc.identifier.other | opendissertations/3815 | en_US |
dc.identifier.other | 4832 | en_US |
dc.identifier.other | 1720608 | en_US |
dc.identifier.uri | http://hdl.handle.net/11375/8625 | - |
dc.description.abstract | <p>Aryl radicals, generated by abstraction of Br from ortho-substituted bromoarenes, add to an imino functional group (C = N) in the ortho substituent in a competition involving 6-endo closure to the C and 5-exo closure to the N-atom. Absolute rate constants for the 6-endo closure were measured for two systems; k_(6-endo)>10⁸ s⁻¹ (80℃). Rate constants for the competing 5-exo closure were estimated to be 10-100 fold smaller. The utility of the 6-endo closure for the synthesis of tetrahydroisoquinolines was demonstrated with eight aldimine systems. Moreover, 1,2-asymmetric induction with up to 57% of diastereomeric excess was discovered for the 6-endo closure to the C-atom of the CN double bond derived from glyceraldehyde acetonide. Radical cyclization in the lower homologue, wherein the choice was between 4-exo closure to the N-atom and 5-endo closure to the C-atom, was not competitive with either 1,5 H-atom transfer of the azomethine proton (aldimine) or transfer of H-atom from Bu₃SnH (ketimine). In the isomeric imines, wherein the choice was between 5-exo closure to the C-atom and 6-endo to the N-atom, aryl radical closure was shown to be exclusively in the 5-exo sense. The absolute rate constant for the 5-exo closure to the C-atom was measured to be 5.3x10⁸ s⁻¹ (80℃). Finally, bis(tributylstannyl)benzopinacolate (TBBP) was found to be a novel source of canned tributylstannyl radicals.</p> | en_US |
dc.subject | Chemistry | en_US |
dc.subject | Chemistry | en_US |
dc.title | Radical cyclization to the imino functional group | en_US |
dc.type | thesis | en_US |
dc.contributor.department | Chemistry | en_US |
dc.description.degree | Doctor of Philosophy (PhD) | en_US |
Appears in Collections: | Open Access Dissertations and Theses |
Files in This Item:
File | Size | Format | |
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fulltext.pdf | 4 MB | Adobe PDF | View/Open |
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