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DC Field | Value | Language |
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dc.contributor.advisor | Warkentin, John | en_US |
dc.contributor.author | El-Saidi, Manal M.T. | en_US |
dc.date.accessioned | 2014-06-18T16:42:08Z | - |
dc.date.available | 2014-06-18T16:42:08Z | - |
dc.date.created | 2010-10-18 | en_US |
dc.date.issued | 1996-03 | en_US |
dc.identifier.other | opendissertations/3423 | en_US |
dc.identifier.other | 4438 | en_US |
dc.identifier.other | 1609143 | en_US |
dc.identifier.uri | http://hdl.handle.net/11375/8200 | - |
dc.description.abstract | <p>Oxadiazolines (I-III), which are novel thermal sources of dioxycarbenes, were synthesized by the exchange method using the acetoxy analogue. The thermal fragmentation of 2,2-dialkoxy oxadiazolines was established to be unidirectional. At $100\sp\circ$C, oxadiazolines (I) decomposed forming nitrogen, acetone, and alkoxymethoxycarbenes as deduced from the identification of the carbene dimers MeO(OR)C=C(OR)OMe.* On the other hand, thermolysis of the aryloxymethoxy oxadiazolines (II) was a multidirectional fragmentation process, with the aryloxymethoxycarbene formation as the major course. A competitive fragmentation afforded the methyl aryl carbonate and diazopropane. The thermal chemistry of the benzyloxymethoxy oxadiazolines (III) is similar to that of the aryloxymethoxy analogue (II). The oxadiazoline (III) loses N$\sb2$ thermally, and also produces acetone and the benzyloxymethoxycarbene via the carbonyl ylide. In addition, the carbene rearranges producing the corresponding ester via 1,2-benzyl group migration to the carbene centre. This rearrangement is a substituent dependent process which is enhanced by electron donating groups. The intermolecular reactions of aryloxymethoxycarbene (IV) with alkynes resulted in a regioselective generation of a 3,3-dioxyvinylcarbene (V or VI). This carbene can either undergo an intramolecular nucleophilic aromatic substitution and/or further reaction with the alkyne. The reaction pathway of (V or VI) is strongly dependent on the nature of the substituent $\rm(R\sp\prime).$* Finally, the aryloxymethoxycarbenes were trapped inter- and intramolecularly via OH insertion reactions. ftn*Please refer to dissertation for diagrams.</p> | en_US |
dc.title | Synthesis and thermolysis of 2,2-dioxy-5,5-dimethyl-delta(3)-1,3,4-oxadiazolines: Dioxycarbenes and their reactions | 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 |
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fulltext.pdf | 4.16 MB | Adobe PDF | View/Open |
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