The protocol of micro-flow nucleophilic pentafluoroethylation using pentafluoroethane (HCF, HFC-125), a nontoxic, inexpensive, and commercially available greenhouse gas, is described. The micro-flow pentafluoroethylation by HFC-125 proceeded smoothly at room temperature or at -10 °C in DMF or toluene in the presence of a potassium base, namely, BuOK or KHMDS. A broad range of ketones, aldehydes, and chalcones with various substituted benzene rings were successfully converted to the corresponding pentafluoroethyl carbinols instantly with good to high yields.
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http://dx.doi.org/10.1021/acs.joc.1c00728 | DOI Listing |
Nat Commun
January 2022
Department of Chemistry, University of Science and Technology of China, Hefei, 230026, China.
Under visible light irradiation, o-phosphinophenolate functions as an easily accessible photoredox catalyst to activate trifluoromethyl groups in trifluoroacetamides, trifluoroacetates, and trifluoromethyl (hetero)arenes to deliver corresponding difluoromethyl radicals. It works in relay with a thiol hydrogen atom transfer (HAT) catalyst to enable selective defluoroalkylation and hydrodefluorination. The reaction allows for the facile synthesis of a broad scope of difluoromethylene-incorporated carbonyl and (hetero)aromatic compounds, which are valuable fluorinated intermediates of interest in the pharmaceutical industry.
View Article and Find Full Text PDFJ Org Chem
October 2021
Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Gokiso, Showa-Ku, Nagoya 466-8555, Japan.
The protocol of micro-flow nucleophilic pentafluoroethylation using pentafluoroethane (HCF, HFC-125), a nontoxic, inexpensive, and commercially available greenhouse gas, is described. The micro-flow pentafluoroethylation by HFC-125 proceeded smoothly at room temperature or at -10 °C in DMF or toluene in the presence of a potassium base, namely, BuOK or KHMDS. A broad range of ketones, aldehydes, and chalcones with various substituted benzene rings were successfully converted to the corresponding pentafluoroethyl carbinols instantly with good to high yields.
View Article and Find Full Text PDFJ Org Chem
April 2021
Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-8555, Japan.
A simple protocol to overcome the explosive pentafluoroethylation of carbonyl compounds by HFC-125 is described. The use of potassium (K) bases with triglyme or tetraglyme as a solvent safely yields the pentafluoroethylation products in good to high yields. The experimental results suggest that an encapsulation of the K cation by glymes as K(glyme) inhibits the contact between the K cation and the reactive anionic pentafluoroethyl counterion, preventing their transformation into KF and explosive tetrafluoroethylene (TFE).
View Article and Find Full Text PDFFuture Med Chem
July 2010
KLIE, Montreal, Quebec, Canada.
Peptidyl inhibitors of the hepatitis C virus NS3 protease hold much promise as direct-acting antiviral agents against hepatitis C infection. The optimization of N-terminal cleavage products, found to exhibit activity (product inhibition) against the enzyme, has led to potent tripeptide inhibitors that bear free C-terminal carboxylate groups. An analogous activated carbonyl compound (pentafluoroethyl ketone) bearing a P1 norvaline (Nva) was found to possess comparable activity against hepatitis C virus protease.
View Article and Find Full Text PDFJ Phys Chem B
July 2010
Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India.
Rotational dynamics of two organic solutes, rhodamine 110 (R110) and 2,5-dimethyl-1,4-dioxo-3,6-diphenylpyrrolo[3,4-c]pyrrole (DMDPP), has been investigated as a function of temperature in a series of 1-alkyl-3-methylimidazolium ionic liquids (alkyl = ethyl, butyl, hexyl, and 2-hydroxyethyl) containing tris(pentafluoroethyl)trifluorophosphate (FAP) anion. The present study has been essentially undertaken to examine the influence of specific interactions on the rotation of cationic (R110) and neutral (DMDPP) solutes in this new class of ionic liquids. Analysis of the results using the Stokes-Einstein-Debye hydrodynamic theory indicates that the rotational dynamics of R110 is closer to the stick boundary condition whereas the dynamics of DMDPP is described by the slip boundary condition.
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