Nucleophilic tetrafluoroethylation of carbonyl compounds with fluorinated sulfones

Zinc 1,1,2,2-Tetrafluoroethanesulfinate: A Synthetically Useful Oxidative and Photoredox Source of the 1,1,2,2-Tetrafluoroethyl Radical

1,1,2,2-Tetrafluoroethyl-containing molecules are of potential importance in drug discovery, but the efficient synthesis of such compounds is still relatively unexplored due to the lack of readily available reagents for the incorporation of the HCF2CF2 group. Herein, we introduce a new reagent, zinc 1,1,2,2-tetrafluoroethanesulfinate, which can be useful for the oxidative tetrafluoroethylation of arylboronic acids and heteroarenes as well as for a novel photoredox, three component hydro-tetrafluoroethylation of two alkenes of complementary reactivity.

Visible-Light-Induced Three-Component Tetrafluoroethyl-heteroarylation of Alkenes with 1,1,2,2-Tetrafluoroethanesulfonyl Chloride and Quinoxalin-2(1H)-ones

1,1,2,2-Tetrafluoroethyl-containing compounds are valuable structures due to their unique physicochemical properties, which have increasing potential application in drug discovery. However, synthetic methods for preparing such compounds are rare. Herein, we report the first use of 1,1,2,2-tetrafluoroethanesulfonyl chloride to introduce the HCF2 CF2 group into organic molecules via a three-component, radical tetrafluoroethyl-heteroarylation of alkenes with readily available quinoxalin-2(1H)-ones. This method provides a new and facile approach for late-stage functionalization of potential biologically active molecules.

Synthesis of tetrafluoroethylene- and tetrafluoroethyl-containing azides and their 1,3-dipolar cycloaddition as synthetic application

Tetrafluoroethylene-containing azides are accessed in two steps (one pot) from tetrafluoroalkyl bromides by metalation and reaction with electrophilic azides. Subsequent copper(i)-catalyzed azide-alkyne cycloaddition afforded N-tetrafluoroethyl and N-tetrafluoroethylene 4-substituted 1,2,3-triazoles. In addition, the protocol for the synthesis of 4,5-disubstituted 1,2,3-triazoles is presented.

Green Ultrasound versus Conventional Synthesis and Characterization of Specific Task Pyridinium Ionic Liquid Hydrazones Tethering Fluorinated Counter Anions: Novel Inhibitors of Fungal Ergosterol Biosynthesis

A series of specific task ionic liquids (ILs) based on a pyridiniumhydrazone scaffold in combination with hexafluorophosphate (PF₆-), tetrafluoroboron (BF₄-) and/or trifluoroacetate (CF₃COO-) counter anion, were designed and characterized by IR, NMR and mass spectrometry. The reactions were conducted under both conventional and green ultrasound procedures. The antifungal potential of the synthesized compounds 2-25 was investigated against 40 strains of Candida (four standard and 36 clinical isolates). Minimum inhibitory concentrations (MIC90) of the synthesized compounds were in the range of 62.5-2000 μg/mL for both standard and oral Candida isolates. MIC90 results showed that the synthesized 1-(2-(4-chlorophenyl)-2-oxoethyl)-4-(2-(4-fluorobenzylidene)hydrazinecarbonyl)-pyridin-1-ium hexafluorophosphate (11) was found to be most effective, followed by 4-(2-(4-fluorobenzylidene)hydrazinecarbonyl)-1-(2-(4-nitrophenyl)-2-oxoethyl)-pyridin-1-ium hexafluorophosphate (14) and 1-(2-ethoxy-2-oxoethyl)-4-(2-(4-fluorobenzylidene)hydrazinecarbonyl)pyridin-1-ium hexafluorophosphate (8). All the Candida isolates showed marked sensitivity towards the synthesized compounds. Ergosterol content was drastically reduced by more active synthesized compounds, and agreed well with MIC90 values. Confocal scanning laser microscopy (CLSM) results showed that the red colored fluorescent dye enters the test agent treated cells, which confirms cell wall and cell membrane damage. The microscopy results obtained suggested membrane-located targets for the action of these synthesized compounds. It appears that the test compounds might be interacting with ergosterol in the fungal cell membranes, decreasing the membrane ergosterol content and ultimately leading to membrane disruption as visible in confocal results. The present study indicates that these synthesized compounds show significant antifungal activity against Candida which forms the basis to carry out further in vivo experiments before their clinical use.

Nucleophilic Tetrafluoroethylation Employing in Situ Formed Organomagnesium Reagents

Tetrafluoroalkyl bromides are metalated with equimolar iPrMgCl·LiCl (Turbo Grignard) to form organomagnesium compounds which are stable at low temperatures and react with various electrophiles (aldehydes, ketones, CO₂, cyclic sulfate and sulfamidate, N-sulfonylimines, nitrone, chlorophosphate, nonaflyl azide) to afford novel functionalized tetrafluoroethylene-containing products. Ease of operation, excellent selectivity, high nucleophilicity, and enhanced stability of the reactive species together with a broad substrate scope comprise a highly attractive nucleophilic tetrafluoroethylation protocol affording unique synthetic building blocks.

Three-component synthesis of fluorinated pyrazoles from fluoroalkylamines, NaNO2 and electron-deficient alkynes

Three-component synthesis of fluorinated pyrazoles.