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Hydrogendifluorides

Bruns and Haufe have described the first examples of a transition metal complex mediated asymmetric ring opening (ARO) of both meso- and racemic epoxides via formal hydro-fluorination [23]. Initial attempts with chiral Euln complexes led to very low asymmetric induction. Opening of cyclohexene oxide 30 with potassium hydrogendifluoride in the presence of 18-crown-6 and a stoichiometric amount of Jacobsens chiral chromium salen complex 29 [24a] finally yielded two products 31 and 32 in a 89 11 ratio and 92% combined yield, the desired product 31 being formed with 55% ee. Limiting 29 to a catalytic amount of 10 mol% led to an increase in the ratio of 31, however, with the enantiomeric excess dropping to 11% (Scheme 5). [Pg.205]

Kalium-hydrogendifluorid (KHF2) reagiert mit Phosphonigsaure- und Phosphinigsaure-fluoriden zu hexakoordinierten Hydridophosphaten21 ... [Pg.904]

Fig. 26 Neutral anion receptor consisting of two tetraamide macrocycles linked by two ethylenediamine spacers (15) [58] (a) crystal structure of uncomplexed 15 (b) crystal structure of the hydrogendifluoride complex [15—FHFI, in which each fluorine atom is bound to only two N-H fragments of the proximate tetraamide macrocycle (c) lateral and (d) top views, highlighting the interaction of HF2- with N-H fragments... Fig. 26 Neutral anion receptor consisting of two tetraamide macrocycles linked by two ethylenediamine spacers (15) [58] (a) crystal structure of uncomplexed 15 (b) crystal structure of the hydrogendifluoride complex [15—FHFI, in which each fluorine atom is bound to only two N-H fragments of the proximate tetraamide macrocycle (c) lateral and (d) top views, highlighting the interaction of HF2- with N-H fragments...
The bifluoride ion (hydrogendifluoride, [HF2]), offers a simple example that permits the mathematics to be worked through in detail. [Pg.41]

Ammonium Acid Fluoride Ammonium Bifluoride Ammonium Fluoride Ammonium Fluoride, Acidic Ammonium Hydrogen Fluoride Ammonium Hydrogendifluoride Amoniak Amphedrine... [Pg.33]

Such formation of both isomers of the cleavage products has been observed in the reactions with weak nucleophiles such as the hydrogendifluoride anion, which requires harsh reaction conditions to complete the cleavage. ... [Pg.61]

The bifluorides syn. hydrogendifluorides, are crystalline solids containing the HF2 species. Examples include sodium bifluoride and potassium bifluoride. They are crystalline solids soluble in water or water-alcohol solutions and extremely corrosive to metals, glass, and other siliceous materials. They are used as etchants. [Pg.130]

Ammonium Hydrogendifluoride. 1727 60 Ammonium Nitrate -Sulfate Mixture 2069 43... [Pg.704]

See other pages where Hydrogendifluorides is mentioned: [Pg.61]    [Pg.523]    [Pg.523]    [Pg.512]    [Pg.10]    [Pg.107]    [Pg.114]    [Pg.61]    [Pg.1022]    [Pg.221]    [Pg.32]    [Pg.299]    [Pg.785]    [Pg.334]    [Pg.106]    [Pg.113]    [Pg.128]    [Pg.46]    [Pg.1022]    [Pg.704]    [Pg.704]    [Pg.723]    [Pg.736]    [Pg.771]    [Pg.778]    [Pg.420]   
See also in sourсe #XX -- [ Pg.8 , Pg.128 , Pg.130 ]



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Hydrogendifluorides, solution

Worked example—hydrogendifluoride (bifluoride) ion

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