23 research outputs found

    Neutral organic super electron donors made catalytic

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    Neutral organic super electron donors (SEDs) display impressive reducing power but, until now, it has not been possible to use them catalytically in radical chain reactions. This is because, following electron transfer, these donors form persistent radical cations that trap substrate-derived radicals. This paper unlocks a conceptually new approach to super electron donors that overcomes this issue, leading to the first catalytic neutral organic super electron donor

    Original formation of benzyl benzoates by TDAE strategy.

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    The dual role of thiourea in the thiotrifluoromethylation of alkenes

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    Alkenes substituted with a thiourea undergo C-CF3 followed by intramolecular C-S bond formation with the Togni reagent and trifluoroacetic acid (TFA) at room temperature; thiols and thioamides are not suitable S-sources for this reaction. This anti-addition process involves a CF3 radical, and affords CF3-substituted thiazolines and thiazines for medicinal applications. A metal or photoredox catalyst is not required as the thiourea acts as a reductant, as well as serving as an S-source capable of adding to a C-centered radical. Mechanistic work comparing the reactivity of thiourea, urea, thioamide and thiol in the context of alkene trifluoromethylation demonstrates that in this series, the thiourea is unique for its ability to release CF3 radical from the Togni reagent, and to orchestrate trifluoromethylation followed by S-cyclization with both activated and unactivated alkenes

    A Rapid Entry to Diverse γ‐Ylidenetetronate Derivatives through Regioselective ­Bromination of Tetronic Acid Derived γ‐Lactones and Metal‐Catalyzed Postfunctionalization

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    International audienceThe synthesis of a series of diverse methyl and benzyl γ‐ylidenetetronate derivatives was accomplished through the condensation of methyl and benzyl tetronates with (hetero)aryl aldehydes in a new two‐ or three‐step aldolisation/dehydration sequence. The bromination of methyl and benzyl γ‐ylidenetetronates occurred under mild conditions to provide the corresponding C‐3‐brominated γ‐unsaturated lactones. Di‐ and tribrominated γ‐lactones were prepared under slightly different conditions. Some brominated materials were employed in representative Stille, Suzuki–Miyaura, and Sonogashira cross‐coupling reactions to yield functionalized methyl and benzyl γ‐ylidenetetronate derivatives. Compounds that resulted from the Sonogashira cross‐coupling reactions were desilylated and converted into 1,2,3‐triazole derivatives through a copper(I)‐catalyzed 1,3‐dipolar cycloaddition reaction with benzyl azide

    Polymer electrolytes based on new aryl-containing lithium perfluorosulfonates

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    International audienceThe electrochemical performances of a broad family of new perfluorosulfonate lithium salts bearing an aryl substituent have been investigated. They exhibit, in polymer electrolytes based on POE, high cationic transference numbers, and fairly good cationic conductivities. The electrochemical stability window of some of them is compatible with their use in lithium batteries having lithium metal as negative electrode. The versatility of the syntheses will allow modulating their physico-chemical properties.The paper gathers new results obtained from a series of aryl-containing lithium perfluorosulfonates dissolved in a macromolecular solvent i.e. poly(oxyethylene). The anion syntheses starting from an aryl sulphide or an aryl ketone, a variety of new salts can be designed by changing the nature of the aryl moiety

    The dual role of thiourea in the thiotrifluoromethylation of alkenes

    No full text
    Alkenes substituted with a thiourea undergo C-CF3 followed by intramolecular C-S bond formation with the Togni reagent and trifluoroacetic acid (TFA) at room temperature; thiols and thioamides are not suitable S-sources for this reaction. This anti-addition process involves a CF3 radical, and affords CF3-substituted thiazolines and thiazines for medicinal applications. A metal or photoredox catalyst is not required as the thiourea acts as a reductant, as well as serving as an S-source capable of adding to a C-centered radical. Mechanistic work comparing the reactivity of thiourea, urea, thioamide and thiol in the context of alkene trifluoromethylation demonstrates that in this series, the thiourea is unique for its ability to release CF3 radical from the Togni reagent, and to orchestrate trifluoromethylation followed by S-cyclization with both activated and unactivated alkenes
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