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
chemical transformation of two HFCs, viz. HFC-23 and HFC-125, based on the continuous-flow perfluoroalkylation of esters to synthesize the pharmaceutically and agrochemically vital trifluoromethyl and pentafluoroethyl ketones. The combination of a potassium base and a glyme solvent system is found to be the most effective. The proposed method is attractive for industrial use because it allows the consumption
A Continuous-Flow Approach to 3,3,3-Trifluoromethylpropenes: Bringing Together Grignard Addition, Peterson Elimination, Inline Extraction, and Solvent Switching
作者:Trevor A. Hamlin、Gillian M. L. Lazarus、Christopher B. Kelly、Nicholas E. Leadbeater
DOI:10.1021/op500190j
日期:2014.10.17
A continuous-flow approach to the synthesis of 3,3,3-trifluoromethylpropenes involving Grignard addition of, (trimethylsilyl)methylmagnesium chloride to a trifluoromethyl ketone followed by dehydrative desilylation of the alpha-trifluoromethyl-beta-hydroxysilyl alcohol using trimethylsilyl trifluoromethanesulfonate is reported. An inline aqueous/organic extraction and a concomitant solvent switch were key to the success of the methodology. Transition from batch to continuous flow conditions allows for higher yields, shorter reaction times, and facile scale out.
Methylenation of Perfluoroalkyl Ketones using a Peterson Olefination Approach
作者:Trevor A. Hamlin、Christopher B. Kelly、Robin M. Cywar、Nicholas E. Leadbeater
DOI:10.1021/jo402577n
日期:2014.2.7
An operationally simple, inexpensive, and rapid route for the olefination of a wide array of trifluoromethyl ketones to yield 3,3,3-trifluoromethylpropenes is reported. Using a Petersonolefination approach, the reaction gives good to excellent yields of the alkene products and can be performed without purification of the β-hydroxysilyl intermediate. The reaction can be extended to other perfluoroalkyl
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