DC Field | Value | Language |
---|---|---|
dc.contributor.advisor | Kim, Sung-Gak | - |
dc.contributor.advisor | 김성각 | - |
dc.contributor.author | Lee, Sang-Phil | - |
dc.contributor.author | 이상필 | - |
dc.date.accessioned | 2011-12-13T04:23:30Z | - |
dc.date.available | 2011-12-13T04:23:30Z | - |
dc.date.issued | 1992 | - |
dc.identifier.uri | http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=59744&flag=dissertation | - |
dc.identifier.uri | http://hdl.handle.net/10203/31199 | - |
dc.description | 학위논문(박사) - 한국과학기술원 : 화학과, 1992, [ v, 213 p. ] | - |
dc.description.abstract | Radical Mediated Ring Expansion Reactions The radical ring expansion reactions of vinyl epoxides were initiated by n-$Bu_3Sn$ radical addition to the vinyl epoxide, followed by epoxide, followed by epoxide fragmantion to the alkoxy radical, β-cleavage to produce the carbon-centered radical, and cyclization. Several noteworthy findings are as follows. First, ring expansion of vinyl oxaspiroheptanes with n-$Bu_3SnH$ and AIBN proceeded cleanly, yielding 2-vinylcyclohexanones in high yields due to the strong preference of 6-exo ring closure over 7-endo closure. Second, β-cleavage of alkoxy radicals occurred at the more highy substituted carbon. Finally, ring expansion of vinyl oxaspirooctane failed due to unfavorable β-cleavage of the alkoxy radical and 7-exo closure. Also, three-carbon ring expansion reactions of silylated vinyl endo epoxides with PhS radical proceeded cleanly, allowing 8-,9-,10-membered rings in high yields. Radical cyclization via Radical Translocations by a Novel 1,5n-$Bu_3Sn$ Group or a 1,5-Hydrogen Atom Transfer. The reaction of the vinyl exo epoxide with n-$Bu_3SnH$ occurred smoothly, yielding initially the alkoxy radical bearing allyltin moiety. 1,5-n-$Bu_3Sn$ transfer proceeded rapidly and cleanly, yielding the allylic radical which underwent reduction, cyclization, and allylation. The vinyl epoxide with a cinnamyl substituent afforded exclusively the 5-exo product whereas allyl substituent afforded a mixture of 5-exo, 6-endo, and ayclized product. The exclusive 6-endo cyclization was realized with methallyl substituent and ayclic compound was not detected. The radical allylation of allyl radical, obtained from 1,5-Sn translocation, with allyltri-n-butylstannane with activated allylstannanes such as 2-carbethoxyallyltri-n-butylstannane and 2-cyanoallyltri-n-butylstannane afforded allylated products. | eng |
dc.language | eng | - |
dc.publisher | 한국과학기술원 | - |
dc.title | Free radical reaction of vinyl epoxides | - |
dc.title.alternative | 비닐폭시드의 자유라디칼 반응 | - |
dc.type | Thesis(Ph.D) | - |
dc.identifier.CNRN | 59744/325007 | - |
dc.description.department | 한국과학기술원 : 화학과, | - |
dc.identifier.uid | 000875298 | - |
dc.contributor.localauthor | Kim, Sung-Gak | - |
dc.contributor.localauthor | 김성각 | - |
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