| LDR | | 04338nam u200421 4500 |
| 001 | | 000000420285 |
| 005 | | 20190215164345 |
| 008 | | 190108s2018 |||||||||||||||||c||eng d |
| 020 | |
▼a 9780438127012 |
| 035 | |
▼a (MiAaPQ)AAI10903095 |
| 035 | |
▼a (MiAaPQ)umichrackham:001237 |
| 040 | |
▼a MiAaPQ
▼c MiAaPQ
▼d 247004 |
| 082 | 0 |
▼a 547 |
| 100 | 1 |
▼a Bour, James R. |
| 245 | 10 |
▼a Accessibility, Reactivity, and Fluoroalkylation Reactions of High-Oxidation-State Organonickel Complexes. |
| 260 | |
▼a [S.l.]:
▼b University of Michigan.,
▼c 2018. |
| 260 | 1 |
▼a Ann Arbor:
▼b ProQuest Dissertations & Theses,
▼c 2018. |
| 300 | |
▼a 217 p. |
| 500 | |
▼a Source: Dissertation Abstracts International, Volume: 79-12(E), Section: B. |
| 500 | |
▼a Adviser: Melanie S. Sanford. |
| 502 | 1 |
▼a Thesis (Ph.D.)--University of Michigan, 2018. |
| 520 | |
▼a A recent resurgence in nickel catalysis research has demonstrated that nickel-based catalyst systems are promising candidates to solve many outstanding problems in cross-coupling catalysis. Mechanistic studies of these transformations often reveal complicated interconversions of short-lived and consequently poorly characterized organometallic nickel intermediates. This observation is particularly true for highly oxidized nickel centers, which rapidly eliminate C--C and C--X bonds. Thus the rational development of methodologies based on high-valent nickel intermediates remains difficult. This dissertation seeks to address these uncertainties through detailed studies on the accessibility, reactivity and interconversions of model NiIII/IV complexes with a specific focus on fluoroalkylation elimination reactions from Ni III/IV centers. |
| 520 | |
▼a Chapter 2 details the synthesis and 1e-- oxidation chemistry of [NiII(CF3)(Ph)] complexes bearing diphosphine or tridentate nitrogen donor ligands. Our studies demonstrate that with a judicious choice of ligand, nickel is able to efficiently mediate the formation of Ar--CF 3 bonds under oxidatively and thermally mild conditions. Stabilization of the proposed intermediates with a tridentate ligand is found to yield the first example of an isolable diorganonickel(III) complex that undergoes C--C coupling. Detailed mechanistic studies of this transformation rule out the potential intermediacy of NiIV in this reaction. |
| 520 | |
▼a Chapter 3 describes the design and reactivity of a model system for a two-part study on elementary organometallic reactions pertinent to Ni II/IV catalysis. Various aryl and alkyl electrophiles are examined for their ability to effect the 2e-- oxidation of NiII to NiIV. The C--C and C(sp3) --X coupling of the reactions of resultant Ni IV(alkyl/aryl) compounds is investigated. Mechanistic studies differentiating 1e-- vs 2e-- pathways of these transformations are described. |
| 520 | |
▼a In Chapter 4 the interconversion of organonickel(III/IV) complexes through their reactions with carbon-centered radicals (CCRs) is reported. First we demonstrate that CCRs effect the oxidation of NiIII to Ni IV through inner-sphere radical addition to the nickel centers. Secondly, we show that select NiIV alkyl complexes are susceptible to homolytic abstraction of a carbon donor ligand by a free carbon-centered radical. This non-traditional C--C coupling pathway opens up previously unprecedented types of reactivity, including mild C--C coupling to form H3C--CF3. |
| 520 | |
▼a Chapter 5 describes the synthesis and reactivity the first isolated examples of a copper(I) difluoromethyl complexes. Key to the realization of this strategy was the implementation of a bulky N-heterocyclic carbene ligand to slow bimolecular decomposition. The stoichiometric reactions of these complexes with a variety of organic electrophiles are described culminating with the catalytic difluoromethylation of aryl iodides. |
| 590 | |
▼a School code: 0127. |
| 650 | 4 |
▼a Organic chemistry. |
| 690 | |
▼a 0490 |
| 710 | 20 |
▼a University of Michigan.
▼b Chemistry. |
| 773 | 0 |
▼t Dissertation Abstracts International
▼g 79-12B(E). |
| 773 | |
▼t Dissertation Abstract International |
| 790 | |
▼a 0127 |
| 791 | |
▼a Ph.D. |
| 792 | |
▼a 2018 |
| 793 | |
▼a English |
| 856 | 40 |
▼u http://www.riss.kr/pdu/ddodLink.do?id=T15013686
▼n KERIS
▼z 이 자료의 원문은 한국교육학술정보원에서 제공합니다. |
| 980 | |
▼a 201812
▼f 2019 |
| 990 | |
▼a ***1012033 |