- Organocatalytic strategy for hydrophenolation of gem-difluoroalkenes
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Gem-difluoroalkenes are an easily accessed fluorinated functional group, and a useful intermediate for elaborating into more complex fluorinated compounds. Currently, most functionalization reactions of gem-difluoroalkenes, with or without a transition metal-based catalyst system, involve the addition or removal of a fluorine atom to generate trifluorinated or monofluorinated products, respectively. In contrast, we present a complementary “fluorine-retentive” reaction that exploits an organocatalytic strategy to add phenols across gem-difluoroalkenes to deliver β,β-difluorophenethyl arylethers. The products are produced in good to moderate yields and selectivities, thus providing a range of compounds that are underrepresented in the synthetic and medicinal chemistry literature.
- Orsi, Douglas L.,Yadav, M. Ramu,Altman, Ryan A.
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- Cobalt-Catalyzed Selective Unsymmetrical Dioxidation of gem-Difluoroalkenes
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gem-Difluoroalkenes represent valuable synthetic handles for organofluorine chemistry; however, most reactions of this substructure proceed through reactive intermediates prone to eliminate a fluorine atom and generate monofluorinated products. Taking advantage of the distinct reactivity of gem-difluoroalkenes, we present a cobalt-catalyzed regioselective unsymmetrical dioxygenation of gem-difluoroalkenes using phenols and molecular oxygen, which retains both fluorine atoms and provides β-phenoxy-β,β-difluorobenzyl alcohols. Mechanistic studies suggest that the reaction operates through a radical chain process initiated by Co(II)/O2/phenol and quenched by the Co-based catalyst. This mechanism enables the retention of both fluorine atoms, which contrasts most transition-metal-catalyzed reactions of gem-difluoroalkenes that typically involve defluorination.
- Altman, Ryan A.,Douglas, Justin T.,Orsi, Douglas L.,Sorrentino, Jacob P.
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p. 10451 - 10465
(2020/09/23)
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- Cross coupling in water: Suzuki-Miyaura vinylation and difluorovinylation of arylboronic acids
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A general and efficient protocol for the Suzuki-Miyaura coupling of aryl boronic acids with vinylmesylate or difluorovinylmesylate or Cl 2CCF2 in water or water/n-butanol is reported, utilizing Na2PdCl4 (1 mol%) and a highly water-soluble fluorenylphosphine (CataCXium F sulf).
- Pschierer, Jan,Peschek, Natalie,Plenio, Herbert
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experimental part
p. 636 - 642
(2010/08/20)
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