Generation of Carbocations under Photoredox Catalysis: Electrophilic Aromatic Substitution with 1-Fluoroalkylbenzyl Bromides
作者:Cuiwen Kuang、Xin Zhou、Qiqiang Xie、Chuanfa Ni、Yucheng Gu、Jinbo Hu
DOI:10.1021/acs.orglett.0c03258
日期:2020.11.6
to access valuable 1-fluoroalkyl-1,1-biaryl compounds is established under mild conditions. The key to success is the efficient generation of a destabilized benzylic carbocation intermediate via two consecutive single-electron transfer processes by virtue of visible-light photoredox catalysis. This unique activation pattern avoids using strong Lewis acids and high temperatures that are required for
Fluoroalkyl alcohols are effectivity oxidized to the corresponding fluoroalkyl carbonyl compounds by reaction with sodium hypochlorite pentahydrate in acetonitrile in the presence of acid and nitroxyl radical catalysts. Although the reaction proceeded slower under a nitroxyl radical catalyst- free condition, the desired carbonyl compounds were obtained in high yields. For the reaction with fluoroalkyl
Photoredox-Catalyzed Ring-Opening Addition Reaction between Benzyl Bromides and Cyclic Ethers
作者:Jinbo Hu、Cuiwen Kuang、Chuanfa Ni、Yucheng Gu
DOI:10.1055/a-1671-6856
日期:2022.3
A novel nucleophilic reaction between cyclic ethers and benzylbromides is achieved under photoredox catalysis. The reaction proceeds through a single-electron-transfer (SET) pathway rather than a common SN2 mechanism. By two steps of reduction and oxidation, a benzylbromide heterolyzes to give a carbocation and bromide ion under mild conditions, and then a cyclic ether captures both the carbocation
Oxidation of α-Trifluoromethyl and Nonfluorinated Secondary Alcohols to Ketones Using a Nitroxide Catalyst
作者:Nicholas E. Leadbeater、Fabrizio Politano、William P. Brydon
DOI:10.1055/s-0042-1752398
日期:2023.5
A methodology for the oxidation of α-trifluoromethyl alcohols to the corresponding trifluoromethyl ketones is presented. A catalytic quantity of a nitroxide is used, and potassium persulfate serves as the terminal oxidant. The methodology proves effective for aromatic, heteroaromatic, and conjugated alcohol substrates. It can be extended to nonfluorinated secondaryalcohols and, in this case, can be