Organomercury Compounds. XXIV Facile syntheses of polyfluoroarylmercurials by mercuration reactions

The polyfluoroarylmercuric chlorides, RHgCl (R = C₆F₅, p-MeOC₆F₄, p-MeC₆F₄, m-HC₆F₄, o-HC₆F₄, p-HC₆F₄, m-O₂NC₆F₄, o-O₂NC₆F₄, p-BrC₆F₄, m-BrC₆F₄, o-BrC₆F₄, p-HOC₆F₄, p-H₂NC₆F₄, m-HO₂CC₆F₄, p-(p-HC₆F₄)C₆F₄, 3,5-H₂C₆F₃, 3-bromo-2,4,6-trifluorophenyl or 3-bromo-2,5,6-trifluorophenyl), and the bis (polyfluorophenyl)mercurials, R₂Hg (R = C₆F₅, p-MeOC₆F₄, p-MeC₆F₄, p-HC₆F₄, m-O₂NC₆F₄,o-O₂NC₆F₄, p-BrC₆F₄, m-BrC₆F₄, o-BrC₆F₄, p-HOC₆F₄, orp-H₂NC₆F₄) have been prepared by mercuration of the appropriate polyfluoroarenes with mercuric trifluoroacetate and trifluoromethanesulphonic acid in trifluoroacetic acid, followed by treatment of the products with hydrochloric acid (RHgCl derivatives) or potassium bromide (R₂Hg derivatives). For R = p-MeOC₆F₄, the actual mercuration product has been isolated and identified as 2,3,5,6-tetrafluoro-4-methoxyphenylmercuric trifluoromethane sulphonate. Interaction of mercuric trifluoroacetate with trifluoromethanesulphonic acid in trifluoroacetic acid yields mercuric trifluoromethanesulphonate, which is considered to be the mercurating agent, and which has been characterized as the complex, [Hg(bpy)₃](O₃SCF₃)₂·H₂0 (bpy = 2,2′-bipyridyl). The mercuration syntheses are very simple and convenient, and should become the preferred method for most polyfluoroarylmercurials.