Cationic ring expansion reactions = 양이온 중간체를 이용한 환상케톤의 고리확장 반응

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The novel methods for the cationic ring expansion of cyclic ketone adducts have been developed. Palladium(0) catalyzed ring expansion of vinyl oxaspirohexanes occurred smoothly in the presence of 1 equiv of p-nitrophenol in tetrahydrofuran, yielding the ring-expanded cyclopentanones in high yields via $\pi$-allylpalladium cationic species. On the other hand, trimethylsilyl ethers of 1-alkenyl-l-cycloalkanols readily rearrange to the ring expanded $\beta$-mercurio cycloalkanones via mercurinium ions and $\beta$-thallium cycloalkanones via thallium ions. For unsymmetrical substrates, the more substituted alkyl group migrates preferentially. $\alpha$-Methylenecycloalkanones were obtained in good yields by elimination of the $\beta$-mercurio or $\beta$-thallium moiety with bases. Also, $\beta$-mercuriocycloalkanines undergo further ring expansion involving free radical reactions in the course of demercuration with $Bu_3SnH$ in methylene chloride. As a synthetic utility, hexahydro-1(2H)-anthracenone was produced via cationic ring expansion and intramolecular nucleophilic participation of a phenyl ring.
Advisors
Kim, Sung-Gakresearcher김성각researcher
Description
한국과학기술원 : 화학과,
Publisher
한국과학기술원
Issue Date
1993
Identifier
68137/325007 / 000875237
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 화학과, 1993.8, [ v, 158 p. ]

URI
http://hdl.handle.net/10203/31375
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=68137&flag=dissertation
Appears in Collection
CH-Theses_Ph.D.(박사논문)
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