Synthesis of biologically active heterocyclic compounds via transition metal-catalyzed carbon-heteroatom bond formation전이금속 촉매 하에서 탄소-헤테로원자 결합 형성을 통한 생리활성 헤테로고리 화합물의 합성에 관한 연구

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Part 1. Synthesis of Heterocyclic-Fused Benzopyrans via the Pd(II)-Catalyzed C-H Alkenylation/C-O Cyclization of Flavones and Coumarins An efficient and practical method for effecting a tandem C-H alkenylation/C-O cyclization has been achieved via the C-H functionalization of flavone derivatives. The synthetic utility of the one-pot sequence was demonstrated by obtaining convenient access to coumarin-annelated benzopyrans. The reaction scope for the transformation was found to be fairly broad, affording good yields of a wide range of flavone- or coumarin-fused benzopyran motifs, which are privileged structures in many biologically active compounds. Part 2. Rh(III)-catalyzed 7-Azaindole Synthesis via C-H Activation/Annulative Coupling of Aminopyridines with Alkynes An efficient Rh(III)-catalyzed 7-azaindole synthesis was developed via C-H activation/annulative coupling of aminopyridines with alkynes. The reaction was highly regioselective and tolerated various functional groups, permitting the construction of various 7-azaindoles. Part 3. Stereoselective Construction of Oxaspirocycles via Chiral Bidentate Directing Group-Mediated C($sp^3$)-O Bond Formation Systematic investigation of chiral bidentate auxiliaries has resulted in the discovery of a chiral 2,2-dimethyl-1-(pyridin-2-yl)propan-1-amine-derived directing group that enables the formation of a stereoselective palladium(II)-catalyzed intramolecular C($sp^3$)-O bond. This new chiral directing group exhibited high reactivity in the activation of methylene C($sp^3$)-H bonds with excellent levels of asymmetric induction (diastereomeric ratio of up to 39:1), which allowed the construction of a wide range of oxaspirocycles. Mechanistic investigations were also conducted to elucidate the reaction mechanism and understand the origin of the diastereoselectivity. DFT-calculations suggest that only modest levels of diastereoselectivity is accomplished at the rate-determining C-H metalation-deprotonation step and the d.r. is further enriched at the reductive elimination step.
Advisors
Hong, Sungwooresearcher홍승우researcher
Description
한국과학기술원 :화학과,
Publisher
한국과학기술원
Issue Date
2018
Identifier
325007
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 화학과, 2018.2,[ii, 66 p. :]

Keywords

C-H activation▼apalladium catalyst▼arhodium catalyst▼aheterocycles▼achiral bidentate directing group; 탄소-수소 활성화▼a팔라듐 촉매▼a로듐 촉매▼a헤테로고리 화합물▼a카이랄 이중배위 지향성기

URI
http://hdl.handle.net/10203/265523
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=734461&flag=dissertation
Appears in Collection
CH-Theses_Ph.D.(박사논문)
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