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Development and Design of Transition Metal-Catalyzed Transformations in Macrocyclizations and Carbon-Carbon Bond Formations
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| 자료유형 | 학위논문 |
|---|---|
| 서명/저자사항 | Development and Design of Transition Metal-Catalyzed Transformations in Macrocyclizations and Carbon-Carbon Bond Formations. |
| 개인저자 | Riedel, Jan. |
| 단체저자명 | University of California, Irvine. Chemistry - Ph.D.. |
| 발행사항 | [S.l.]: University of California, Irvine., 2019. |
| 발행사항 | Ann Arbor: ProQuest Dissertations & Theses, 2019. |
| 형태사항 | 176 p. |
| 기본자료 저록 | Dissertations Abstracts International 81-04B. Dissertation Abstract International |
| ISBN | 9781085654265 |
| 학위논문주기 | Thesis (Ph.D.)--University of California, Irvine, 2019. |
| 일반주기 |
Source: Dissertations Abstracts International, Volume: 81-04, Section: B.
Includes supplementary digital materials. Advisor: Dong, Vy M. |
| 이용제한사항 | This item must not be sold to any third party vendors. |
| 요약 | Cyclic peptides have been recognized for their potential to mimic protein-protein interactions. Traditionally, cyclizations are carried out at high dilution to suppress competitive intermolecular reactions, which makes these cyclizations economically inefficient and hard to perform at scale. We developed the use of dehydro amino acids as traceless turn-inducers to enable macrocyclizations at high concentrations. We demonstrated our strategy in the total synthesis of dichotomin E at cyclization concentrations as high as 0.1~M. In collaboration with Prof. Rachel Martin, we studied the origin of the turn-inducing effect by CD-spectroscopy, NMR and molecular mechanics simulations.Inspired by nature's ability to take a common precursor like geranyl pyrophosphate and cyclize it into an array of natural products (e.g., sabinene, limonene, camphene, and pinene), we expanded the cycloisomerization chemistry of 2-allyl-4-pentenal derivatives. We found that cobalt is a competent catalyst in the synthesis of cyclobutanones over cyclopentanones. We propose a Co(0) active catalyst. Building on this chemistry, we extended our methodology by making bicyclic systems. From a symmetrical starting material we affect a desymmetrization and build trans-fused hydrindanones selectively.Using DFT, we studied the mechanism of a rhodium catalyzed cycloisomerization to understand the structure-selectivity relationship between ligand and reaction outcome. A unprecedented induced-fit mechanism has been found operable, and the insights of these studies led to the design and synthesis of new ligands to access new pathways.Simple unsaturated nitriles play an important role as flavoring agents and precursors for fine chemicals and polymers. Traditional synthesis would involve the use of halides and toxic cyanides. We developed a method that improves previous approaches by using a Cu(II) catalyst and di-tert-butyl peroxide to generate alkyl radicals from alkylnitriles. We used unactivated olefins and simple alkylnitriles in a broad reaction scope through double sp3 C-H activation. Internal as well as terminal olefins are competent coupling partners. We hypothesize, that the high chemo- and regioselectivity comes from a directing group effect of the nitrile to the copper catalyst. |
| 일반주제명 | Chemistry. Organic chemistry. Physiology. Medicine. Epidemiology. Public health. Health sciences. Pathology. |
| 언어 | 영어 |
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