Mechanistic study of the C-H bond functionalization and rearrangement reactions using density functional calculations = 밀도 범함수 이론을 이용한 탄소-수소 결합 활성화 반응과 재배치 반응의 메카니즘에 대한 연구

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Part 1. C?H Bond Activation Mechanism by Rh Catalyst Systems In chapter 2, biarydiazoacetates undergo intramolecular aromatic carbenoid insertion to form fluorene carboxylates in high yields under very mild conditions when the reaction is performed in the presence of catalytic amounts of rhodium(??) acetate or copper(??) triflate. Whereas thermal conditions provide a mixture of two regioisomeric products when substituted biaryldiazoacetates are employed as a substrate, a wide range of susbtituted fluorene carboxylates were efficiently obtained with high selectivity under the catalytic conditions. The insertion mechanism was revealed to be electrophilic aromatic substitution, which was supported by the scrambling study, deuterium kinetic isotope and substituent effects of aromatic ring. Density functional calculations of the cyclization process suggest that the observed regioselectivity can be readily explained in terms of steric interactions between the substituents and sterically demanding rhodium metal species in addition to the electronic induction effects of those substituents. Subsequent issue is a catalytic procedure to introduce organic functional groups into 2,2’-bipyridines and 2,2’-biquinolines, arguably the most representative organic chelating compounds, by using a rhodium catalyst system. The conceptual basis enabling this catalytic conversion is that an initially generated rhodium chelate becomes labile due to the presence of a N-heterocyclic carbene (NHC) ligand that exhibits a strong trans-effect to weaken a rhodium-pyridyl bond trans to NHC. A subsequent rollover cyclometalation process leads to the key C?H bond activation of substrates by the action of the NHC-bound rhodium catalyst. Density functional calculations were in full agreement with the experimental data, and provided additional mechanistic insights. Part 2. Rearrangement Mechanism In chapter 2, we study about new direct trifluoromethylthiolation reaction developed by Shibata ...
Advisors
Jung, You-Sungresearcher정유성
Description
한국과학기술원 : 화학과,
Publisher
한국과학기술원
Issue Date
2014
Identifier
591876/325007  / 020098127
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 화학과, 2014.8, [ vii, 77p. ]

Keywords

분자내 카벤 삽입 반응; 고리금속화 반응; 로듐 촉매; 술포닐그룹의 재배치 반응; 탄소-수소 결합 활성화; 밀도 범함수 이론 계산; 메카니즘 연구

URI
http://hdl.handle.net/10203/196478
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=591876&flag=dissertation
Appears in Collection
CH-Theses_Ph.D.(박사논문)
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