DC Field | Value | Language |
---|---|---|
dc.contributor.advisor | Hong, Sungwoo | - |
dc.contributor.advisor | 홍승우 | - |
dc.contributor.author | Kim, Jiyun | - |
dc.date.accessioned | 2021-05-12T19:31:57Z | - |
dc.date.available | 2021-05-12T19:31:57Z | - |
dc.date.issued | 2019 | - |
dc.identifier.uri | http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=886667&flag=dissertation | en_US |
dc.identifier.uri | http://hdl.handle.net/10203/283746 | - |
dc.description | 학위논문(석사) - 한국과학기술원 : 화학과, 2019.2,[ii, 37 p. :] | - |
dc.description.abstract | Part 1. Bifunctionalization of Alkenes Using Pyridinium Salts $\beta$-Pyridylphosphine derivatives consisting of vicinal pyridine and phosphine group possess soft $\pi$-acceptor properties of phosphines and hard $\sigma$-donor features of pyridines, which are widely employed as ligands in various transition metal complexes. An efficient synthetic method for the construction of $\beta$-pyridylalkylphosphonates was developed via a one-pot three-component reaction between P(O)–H compounds, alkenes and N-heteroarenium salts under mild conditions. The reaction is thought to occur by the addition of a phosphonyl radical to the alkene to form alkyl radical intermediate, which goes on to add to the N-methoxypyridinium salt. This straightforward methodology is applied to a variety of N-heteroarenium salts and alkene substrates to prepare various synthetically and biologically important $\beta$-pyridylalkylphosphonates groups. Part 2. Metal-Free Visible-Light-Induced Pyridylation of Remote C($sp^3$)–H Bonds Using Pyridinium Salts 2.1 Pyridylation of remote C($sp^3$)–H bonds using N-alkoxypyridinium salts Direct C($sp^3$)–H functionalization has been recognized as a powerful tool for various carbon–carbon or carbon–heteroatom bond formation. We introduced a metal-free, visible-light-induced site-selective pyridylation of remote C($sp^3$)–H bonds. The new designed N-alkoxypyridinium salts can serve as both alkoxy radical precursors and pyridiyl sources. The alkoxy radical can be generated via the single electron transfer of an N-alkoxypyridinium substrates by a photoexcited quinolinone catalyst. Subsequent radical translocation of the alkoxy radical forms a nucleophilic alkyl radical intermediate, which undergoes addition to the substrate to achieve remote C($sp^3$)–H pyridylation. This cascade strategy provides a powerful platform for remote C($sp^3$)–H heteroarylation in a controllable and selective manner and is well suited for late-stage functionalization of complex bioactive molecules. 2.2 Pyridylation of C($sp^3$)–H bonds using N-aminopyridinium salts The direct functionalization of C($sp^3$)–H bonds constitutes a powerful and atom-economic approach for the bond formation. Radical translocation processes mediated by heteroatom radicals provide a potential platform for the selective functionalization of remote inert C($sp^3$)–H bonds. We were intrigued by the possibility of developing efficient pathway of remote C($sp^3$)–H bond functionalization by translocation of N-centered radical, introducing pyridinium salt substrate system. The efficient site-selective pyridylation of remote C($sp^3$)–H bonds using N-aminopyridinium salts via photocatalysis was developed. This strategy involves the generation of radical species from pyridinium salts, 1,5-HAT process, and pyridylation to produce C-4 alkylation products. The possibility of α-amino functionalization and cyclization was also observed, and various divergent reactions of N-aminopyridinium salts are under investigation. | - |
dc.language | eng | - |
dc.publisher | 한국과학기술원 | - |
dc.subject | Pyridylation▼aPyridinium salts▼aC($sp^3$)–H bond functionalization▼aRadical cascade reaction▼aPyridine functionalization | - |
dc.subject | 피리딘화 반응▼a피리디늄 염▼a탄소($sp^3$)–수소 결합의 작용기 도입▼a라디칼 연속 반응▼a피리딘 기능화 | - |
dc.title | Photocatalyzed pyridylation of C($sp^3$)–H bonds using pyridinium salts | - |
dc.title.alternative | 피리디늄 염을 사용한 C($sp^3$)–H 결합의 광촉매 피리딘화 반응 | - |
dc.type | Thesis(Master) | - |
dc.identifier.CNRN | 325007 | - |
dc.description.department | 한국과학기술원 :화학과, | - |
dc.contributor.alternativeauthor | 김지윤 | - |
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