The regiochemistry of alkenylsilyl, alkenyldisilanyl and alkenylsilyloxy radical cyclizations

dc.contributor.author Revis, Anthony
dc.contributor.department Chemistry
dc.date 2018-08-15T09:32:06.000
dc.date.accessioned 2020-07-02T06:10:45Z
dc.date.available 2020-07-02T06:10:45Z
dc.date.copyright Sun Jan 01 00:00:00 UTC 1984
dc.date.issued 1984
dc.description.abstract <p>The regiochemistry of intramolecular cyclization of some alkenylsilyl and alkenyldisilanyl radicals has been examined. It has been demonstrated that the silyl radicals produced by hydrogen abstraction from a pentenylsilane, a butenylsilane, a butenyldisilane, an allyldisilane, and a butenyloxysilane all cyclize in an endo-fashion. This is in complete contrast to what is known for the analogous carbon-centered radicals. No cyclic products are observed for chain lengths shorter than five atoms. Also, when alkenyldisiloxanyl and butadienyl-type silyl radicals are generated by pyrolytic cleavage of silicon-allyl bonds, endo-closure is found to be the exclusive mode of cyclization. However, alkenyldisilanyl radicals undergo disproportionation to silenes when generated by pyrolysis of allyldisilanes. The silenes, formed by what is formally a retroene elimination of propene, afford 1,3-disilacyclics via silene to silylene rearrangement;The pyrolysis of 3-butenylsilanes was found to give (alpha)-silyl radicals via carbon-allyl homolysis of the butenyl groups. A 1,2-hydrogen migration from silicon to a carbon-centered radical has been observed for dimethylsilylcarbinyl radical. The radical was produced from 3-butenyldimethylsilane and afforded the first example of this type 1,2-hydrogen shift. Intramolecular endo-cyclization has also been observed to occur for (alpha)-silyl radicals possessing an alkenyl substituent;The pyrolysis of allyloxysilanes was also examined in a search for precursors to alkenylsilyloxy radicals. From this study, allyloxy-allyldimethylsilane was found to be an excellent dimethylsilanone precursor; the initial step being oxygen-allyl cleavage to the corresponding silyloxy radical.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/rtd/9023/
dc.identifier.articleid 10022
dc.identifier.contextkey 6347555
dc.identifier.doi https://doi.org/10.31274/rtd-180813-8965
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath rtd/9023
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/82077
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/rtd/9023/r_8423668.pdf|||Sat Jan 15 02:27:18 UTC 2022
dc.subject.disciplines Organic Chemistry
dc.subject.keywords Chemistry
dc.subject.keywords Chemistry
dc.subject.keywords Organic
dc.title The regiochemistry of alkenylsilyl, alkenyldisilanyl and alkenylsilyloxy radical cyclizations
dc.type article
dc.type.genre dissertation
dspace.entity.type Publication
relation.isOrgUnitOfPublication 42864f6e-7a3d-4be3-8b5a-0ae3c3830a11
thesis.degree.level dissertation
thesis.degree.name Doctor of Philosophy
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