Perfluoro alkyl iodides

The conventional procedure involves 5 steps via telomerization of perfluoro-alkyl iodide with perfluoroethylene and ethylene followed by oxidation. The estimated scale of perfluorination of C8H17COOH or CH3S03H at a Ni anode in liquid HF in the US, Japan and UK amounts to about 100 tonnes per year cf. Table 8. 

Perfluoro alkyl iodides add to both terminal and internal double bonds when the reaction is initiated by electron transfer from metals such as finely divided silver, copper powder, and lead with copper acetate. Using an -olefin and a perfluoro-alkyl-a, -diiodide, a perfluoro group can be inserted into a long-chain compound (118) (Figure 21). Deiodination of the product by catalytic reduction results in highly hydrophobic alkyl chains with interesting surfactant properties. 

Perfluoro alkanoic acids have been prepared from perfluoro alkyl iodides by carboxylation in the presence of a zinc-copper couple in DMSO, in yields of 50% or greater. 

The reaction of perfluoroalkyl iodides with alkenes affords the perfluoro-alkylated alkyl iodides 931. Q.a-Difluoro-functionalized phosphonates are prepared by the addition of the iododifluoromethylphosphonate (932) at room temperature[778], A one-electron transfer-initiated radical mechanism has been proposed for the addition reaction. Addition to alkynes affords 1-perfluoro-alkyl-2-iodoalkenes (933)[779-781]. The fluorine-containing oxirane 934 is obtained by the reaction of allyl aicohol[782]. Under a CO atmosphere, the carbocarbonylation of the alkenol 935 and the alkynol 937 takes place with perfluoroalkyl iodides to give the fluorine-containing lactones 936 and 938[783]. 

Thiocoumarins react with perfluoroalkyl iodides in the presence of Rongalite, HOClTSC Na, to give 3-perfluoro-alkyl derivatives 279 (Equation 24) <1994J(P1)101>. 

Perfluoroalkyl iodides were demonstrated to be efficient reagents for perfluoro-alkylation of pyridine (8) at elevated temperature (Fig. 7.3). ... 

Standard methods which convert alkylmercury iodides into bis(alkyl)-mercurials fail to convert perfluoroalkylmercury iodides into bis(perfluoro-alkyl)mercurials. The preparation of primary bis(perfluoroalkyl)mercurials can be accomplished by treating perfluoroalkylmercury iodides with silver, copper, or cadmium amalgams. Alternatively, the parent perfluoroalkyl iodide will react directly with the amalgam. By either method yields are from 40 to 90%. 

Copper, Sflver and Gold.—Perfluoroalkyl iodides and iodoaromatic compounds react with copper in aptotic solvents to give good yields of perfluoro-alkylated aromatic compounds ... 

Alkyl iodide, CH3I, C2H3I Allyl chloride, - bromide CH2CI2 1,2-Dihalides (CHs)2CHBrCHBr(CH2)2 Polyhalides, Perfluoro-halides... 

Perfluoroalkyl iodides comprise the most important and commonly-used source of perfluoroalkyl radicals [57-59], and for the most part, the methods which have been developed for such perfluoro systems also work well for generation of partially-fluorinated alkyl radicals from their respective iodides. 

Castro et al. 44) found that the order of reactivity of various halides in coupling reactions with ethynylcopper compounds in DMF is ArSX, ArX > RCOX ArCHaX, RCH=CHCH2X, ArCOCHaX > RCH= CHX, Alkyl-X. A somewhat different order is observed for the reactivity of some organic halides towards perhaloarylcopper reagents in THF (97, 147) Allyl Aryl > Alkyl and perfluoroaryl, perfluoro-vinyl > aryl > perfluoroalkyl. Acid halides were also far more reactive than aryl iodides in ethereal solvents 146). The ease of halide displacement is I > Br > Cl. 

Perfluoro- and polyfluoro-alkyl and -cycloalkyl chlorides, bromides, and iodides are encountered so often as starting materials, derivatives, solvents, products in mechanistic studies, by-products, etc., that it is impracticable to provide a comprehensive coverage of the relevant literature in one section. Readers with a particular interest in fluorocarbon halides are thus advised to browse widely through this volume. Additionally, some of the information collected on chloro- (including environmental effects), bromochloro-, and iodo-compounds has been relegated to appendices (pp. 43, 45, and 46). 

Perfluoro-(l-methylpropenyl)silver undergoes very slow halogen exchange with bromotrichloromethane and 1,2-dibromotetrachloroethane, but gives the tranj-olefins CF3-CF CX CFa (X = Br or H) essentially quantitatively with bromine, water, or hydrogen chloride, and is alkylated with methyl iodide. With cupric bromide it is coupled, presumably via the copper compound CF3 CF CCu-CF3, to give the trfl j,/ra j-isomer of (149). ... 

At low temperatures perfluoro-w-propyllithium, prepared in the above manner, underwent displacement and addition reactions common to alkyl-lithium compounds. The experimental technique (7) involved addii methyllithium and the reactant dissolved in ether to heptafluoro- -propyl iodide in the same solvent. In this manner, certain aldehydes and ketones afforded the expected alcohols, and diethyldichlorosilane gave a mixture of the organosilanes n-C3F7(C2H5)2SiCl and ( -C3F7)2Si(C2H5)2. 

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