Fluoride derivatives from

Fluorinated ether-containing dicarboxyhc acids have been prepared by direct fluorination of the corresponding hydrocarbon (17), photooxidation of tetrafluoroethylene, or by fluoride ion-cataly2ed reaction of a diacid fluoride such as oxalyl or tetrafluorosuccinyl fluorides with hexafluoropropylene oxide (46,47). Equation 8 shows the reaction of oxalyl fluoride with HEPO. A difunctional ether-containing acid fluoride derived from HEPO contains regular repeat units of perfluoroisopropoxy group and is terminated by two alpha-branched carboxylates. 

T. Shioiri, A. Bohsako, A. Ando, Importance of the Hydroxymethyl-quinudidine Fragment in the Catalytic Asymmetric Adol Readions Utilizing Quaternary Ammonium Fluorides derived from Cinchona Akaloids , Heterocycles 1996, 42, 93-97. 

Another stratagem to avoid nonideality of the gas state is to compare heats of formation of fluorides derived from fluorine combustion on the element, with heats of hydrolysis determined directly or indirectly, as in... 

Higher silicon halides Si X +2 with n > 2 but of limited molecular weight have been known for a long time, above all from chlorine, but a few from bromine, and none from iodine. In the case of fluorine, some higher silicon fluorides derived from difluorosilylene have been recently discovered (see p. 60). 

Ferromagnetic Fluorides Derived from the K2NiF4 Type. 108... 

In similar way pcrfluoroclhanecan be produced from perfluoropropanoyl fluoride. This process has also been applied " to high molecular weight molecules and to acyl fluorides derived from polymcrizalion of tetralluoroethylenc oxide. 

Complex Fluorides of Platinum[w).—The most convenient starting material for the preparation of hexafluoroplatinates(v) is dioxygenyl hexafluoroplatinate. This and some of the complex fluorides derived from it have been described in Part II the reactions are represented in the Figure. 

In the laboratory of G.A. Posner, semisynthetic antimalarial trioxanes in the artemisinin family were prepared via an efficient Friedel-Crafts alkylation using a pyranosyi fluoride derived from the natural trioxane lactone artemisinin. The alkylating agent, pyranosyi fluoride, was prepared from the lactone in two steps reduction to the lactol followed by treatment with diethylaminosulfur trifluoride. The highly chemoselective alkylation was promoted by BF3-OEt2 and several electron-rich aromatic and heteroaromatic compounds were alkylated in moderate to high yield using this method. 

Fig. 14.—The Valence Geometry Parameters in Two Forms of D-Xylopyranosyl Fluoride Derivatives (from Ref. 98).

Lewis add complexes formed by the reactions of various aminoalcohols with Et2AlG [778, 824] or by the reaction of Et2Zn with a chiral sulfamide [806] have displayed a low efficiency in the asymmetric condensations of ketene and thioketene silyiacetals derived from acetic acid with aldehydes. Disappointing se-lectivities have also been observed with some binaphtol-titanium complexes [778]. However, Mikami and Matsukawa [1296] recently performed the enantioselective condensation of various aldehydes with acetic acid derivatives in the presence of a chiral binaphtol-titanium complex. Good selectivities were observed when the reaction was performed at 0°C in toluene (Figure 6.95). Quaternary ammonium fluorides derived from cinchona alkaloids have been proposed as catalysts to perform additions of enoxysilanes derived from ketones to PhCHO, but the observed selectivities are modest [1303],... 

Fig. (51). Scutione and fluoride derivatives from Maytenus scutioides...

In the acid medium of PEM fuel cells that may also contain some levels of fluoride derived from membrane degradation, Pt cannot be replaced with a non-noble metal or a metallic oxide, as both will corrode in such environment. This chapter describes some of the efforts that have been made over 40 years to obtain other non-precious metal electrocatalysts for ORR in acidic medium. They aU started with the discovery in 1964 that C0N4 phthalocyanine was capable of oxygen reduction in an alkaline solution. ... 

Although there has been some recent interest in the catalytic fluorination of CCI4, notably over chromium(III) fluoride derived from thermal decomposition of (NH4)3CrF6 [42], most attention has been paid to dismutations within the HCFC—CHCl3 F series. Reactions on several metal oxides and halides have been studied by Kemnitz and coworkers and evidence for dismutation behaviour adduced from thermodynamic considerations and... 

Non-fluoride initiators have been employed satisfactorily as well, including Lewis bases (amines, amine A-oxides, carbonates and phosphates," LiOAc," " f-BusF ), Lewis acids," A-heterocyclic carbenes, or even without initiator in DMSO as solvent. The addition of TMSCF3 to carbonyl compounds in the presence of a chiral initiator allows the enantioselective preparation of trifluoromethyl alcohols. For this purpose, quaternary ammonium fluorides derived from cinchona alkaloids (1) have been employed, affording moderate (up to 51% ee) " to high enantioselectivities (up to 92% ee). Also, the corresponding bromides were used in combination with an external fluoride source (KF or TMAF, up to 94% ee) or with disodium (R)-binaphtholate (up to 71% ee), or simply a cinchonidine-derived ammoniumphenoxide (up to 87% ee). Moreover, the use of a chiral TASF derivative (2) has also been reported (up to 52% ee). ... 

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