Studies on development of new synthetic method of 1,3-Diyl and application to organic synthesis = 1,3-다이일의 새로운 합성 방법 개발과 유기합성에의 응용에 관한 연구

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Cycloaddition reaction of alkylidene carbenes generated from alkynyliodonium salts has been studied. Intramolecular cycloaddition of alkylidene carbene to an olefin affords 1,3-diyl by homolytic cleavage of adduct. This 1,3-diyl is trapped by the other olefin, diylophile in a proper position to produce triquinane, and moreover preparation of the tetraquinane framework of Crinipellin with proper stereochemistry has been achieved. In case of triquinane synthesis, isocapnellenone, X-ray crystallography showed the unexpectedly trans, syn, cis-fused ring junction triquinane since the reaction utilizing with intramolecular diyl trapping reaction via alkylidene carbene was affected severely by steric influence. Therefore, with a very careful design, it will be possible to prepare the product with a mixed ring junction stereochemistry. This method provides a good synthetic strategy to construct polyquinane skeletons, but it exhibits the several disadvantages such as functional group transformations and relatively low product yields. Therefore, alternative generation method of 1,3-diyl was needed to apply for synthesis of natural product. A new efficient way to generate TMM diyls was developed with allenes and N-aziridinylimines and successfully utilized in [2+3] cycloaddition reaction with olefins. The novel one pot sequential transformation of thermally labile pyrazoles obtained through [2+3] cycloaddition reaction of diazoalkanes with allenes produced TMM diyls and the generated diyls were trapped by olefin to form polyquinanes. Total synthesis of (±)-ceratopicanol, linear triquinane natural product, was successful through 11 steps from pentynal. Triquinane core structure was assembled by thermolysis of allenyl aziridinylimine. And also, the preparation of the tetraquinane framework of Crinipellin with proper stereochemistry was succeeded with new methodology to generate TMM diyl from allene and N-aziridinylimine.
Advisors
Lee, Hee-Yoonresearcher이희윤researcher
Description
한국과학기술원 : 화학과,
Publisher
한국과학기술원
Issue Date
2007
Identifier
263553/325007  / 020025819
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 화학과, 2007.2, [ iv, 279 p. ]

Keywords

alkylidene carbene; allene; 1,3-diyl; triquinane,; 트리퀴난; 알킬리덴 카벤; 알렌; 1,3-다이일

URI
http://hdl.handle.net/10203/31676
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=263553&flag=dissertation
Appears in Collection
CH-Theses_Ph.D.(박사논문)
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