Versatile asymmetric synthesis of polyoxygenated bioactive natural products and their analogs다중산소 치환기를 가지는 생리활성 천연물들과 그 유도체의 다양한 비대칭합성에 관한 연구

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It is well documented that epoxides play a paramount role for the synthesis of various natural products. Enantioselective synthesis of δ-lactone natural products utilizing epoxides as key intermediates has been described. This protocol provides access to two different classes of δ-lactones such as mevinic acid analogs in which the δ-lactone functionality is attached with simple alkyl units and polyketide natural products in which the α,β-unsaturated δ-lactone is connected with $\sl{syn}$ 1,3-polyols. Both classes of natural products possess broad range of biological activity. A short stereoselective synthesis of mevinic acid analogs was developed adopting a chiral pool approach. We utilized commercially available chiral epichlorohydrin as the chiral pool. The installation of the alkyl units was accomplished $\sl{via}$ organocuprate mediated epoxide opening. The back bone of the mevinic acid analogs was constructed $\sl{via}$ birch reduction followed by the chelation controlled reduction. Having developed a simple route to mevinic acid analogs, the scope of the strategy was elaborated for the synthesis of cryptocarya diacetate. The synthesis of this polyketide natural product was achieved in 10 steps. This straightforward route involves iterative epoxide opening, birch reduction and highly diastereoselective chelation controlled reduction of diketone. Generality of the synthetic strategy was demonstrated in the synthesis of tarchonanthuslactone, another important polyketide natural product with two acyloxy groups in a 1,3- $\sl{syn}$ relationship. An elegant synthesis of this natural product has been achieved in 9 linear steps, making it more efficient than the published route. This synthesis incorporates iterative epoxide opening, mercury catalyzed hydration of alkyne followed by the chelation controlled reduction. Construction of the lactone moiety includes Lindlar hydrogenation followed by acid catalyzed lactonization. We have applied a powerful meth...
Advisors
Lee, Hee-Yoonresearcher이희윤researcher
Description
한국과학기술원 : 화학과,
Publisher
한국과학기술원
Issue Date
2009
Identifier
309373/325007  / 020054505
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 화학과, 2009.2, [ 187 p. ]

Keywords

Enantioselectivity; Polyketides; Chelation; Asymmetric; epoxide; 입체선택성; 폴리케타이드; 킬레이션; 비대칭; 에폭사이드; Enantioselectivity; Polyketides; Chelation; Asymmetric; epoxide; 입체선택성; 폴리케타이드; 킬레이션; 비대칭; 에폭사이드

URI
http://hdl.handle.net/10203/31722
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=309373&flag=dissertation
Appears in Collection
CH-Theses_Ph.D.(박사논문)
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