| LDR | | 00000nam u2200205 4500 |
| 001 | | 000000433963 |
| 005 | | 20200226134645 |
| 008 | | 200131s2019 ||||||||||||||||| ||eng d |
| 020 | |
▼a 9781085755771 |
| 035 | |
▼a (MiAaPQ)AAI22584402 |
| 040 | |
▼a MiAaPQ
▼c MiAaPQ
▼d 247004 |
| 082 | 0 |
▼a 547 |
| 100 | 1 |
▼a Tay, Nicholas Eng Soon. |
| 245 | 14 |
▼a The Development of Selective Aromatic Functionalizations in Acridinium-mediated Photoredox Catalysis. |
| 260 | |
▼a [S.l.]:
▼b The University of North Carolina at Chapel Hill.,
▼c 2019. |
| 260 | 1 |
▼a Ann Arbor:
▼b ProQuest Dissertations & Theses,
▼c 2019. |
| 300 | |
▼a 525 p. |
| 500 | |
▼a Source: Dissertations Abstracts International, Volume: 81-03, Section: B. |
| 500 | |
▼a Advisor: Nicewicz, David A. |
| 502 | 1 |
▼a Thesis (Ph.D.)--The University of North Carolina at Chapel Hill, 2019. |
| 506 | |
▼a This item must not be sold to any third party vendors. |
| 520 | |
▼a Aromatic rings are important molecular components of many pharmaceuticals, agrochemicals, organic materials and natural products, and the development of selective arene functionalization transformations has been broadly applied in basic and translational research. Photoredox catalysis is an invaluable synthetic tool for the activation of organic molecules via single electron redox pathways. This synthetic strategy enables the construction of carbon-carbon and carbon-heteroatom bonds with orthogonal reactivity to classical two-electron pathways. An introduction to both topics is provided in the first two chapters.The Nicewicz lab has recently developed a variety of transformations that proceed by reactive cation radical species. These systems rely on the ability of an acridinium photoredox catalyst to promote single electron oxidation of a target organic substrate by photoinduced electron transfer. Noting the importance of aromatic molecules, we sought to develop photoredox-catalyzed chemo- and site- selective arene functionalizations that proceed through arene radical cations. As a result, two general reaction methodologies emerged from our investigations into the reactivity of arene radical cations: selective aromatic carbon-hydrogen (C-H) bond and carbon-oxygen (C-O) bond functionalizations.These photoredox-catalyzed aryl C-H amination and C-H (radio)fluorination reactions feature the use of a nitroxyl radical co-catalyst and oxygen to achieve a net oxidative transformation, which furnishes aryl amines and radiolabeled fluoroarenes with high site- selectivity. A diverse range of arenes were compatible with both transformations and the application of 18F-labeled aromatics to positron emission tomography (PET) imaging was demonstrated. These two projects are covered in Chapters 3 and 5.Photoredox-catalyzed aryl C-O functionalizations occur by a complementary strategy to nucleophilic aromatic substitution (SNAr). The generation of arene radical cations enables an inversion of traditional SNAr selectivities such that electron-rich aromatics are selectively functionalized at an electron-donating C-O bond-containing substituent. This reaction mode enables the synthesis of aryl amines, fluoroarenes, and [18F]fluoroarenes. Additionally, we demonstrate that this reactivity pattern is dependent on the presence of a terminal oxidant, wherein its exclusion promotes selective C-O substitution over C-H functionalization. These two projects are covered in Chapters 4 and 6. |
| 590 | |
▼a School code: 0153. |
| 650 | 4 |
▼a Organic chemistry. |
| 690 | |
▼a 0490 |
| 710 | 20 |
▼a The University of North Carolina at Chapel Hill.
▼b Chemistry. |
| 773 | 0 |
▼t Dissertations Abstracts International
▼g 81-03B. |
| 773 | |
▼t Dissertation Abstract International |
| 790 | |
▼a 0153 |
| 791 | |
▼a Ph.D. |
| 792 | |
▼a 2019 |
| 793 | |
▼a English |
| 856 | 40 |
▼u http://www.riss.kr/pdu/ddodLink.do?id=T15492840
▼n KERIS
▼z 이 자료의 원문은 한국교육학술정보원에서 제공합니다. |
| 980 | |
▼a 202002
▼f 2020 |
| 990 | |
▼a ***1008102 |
| 991 | |
▼a E-BOOK |