Fluoroalkyl iodide

Fluoroalkyl iodides are oxidized at the iodine atom by trifluoroperoxyacetic... 

The Hunsdieckers method for replacing a carboxyl group by a halogen has been applied to the preparation of simple fluoroalkyl iodides [44], fluoroiodoalkyl ethers [45], and fluorovinyl iodides [46] (equations 27 -29)... 

Many reactions of fluorinated organics with metal halides result in the replacement of fluorine with halogen A general route to 1,1,1-trichloro- or tribromo-fluoroalkanes involves treating primary fluoroalkyl iodides with aluminum trichloride or aluminum tribromide [74], Benzylic [75, 76] or vinylic [72] fluorine can be exchanged for chlorine when treated with aluminum trichloride... 

Metal halides can in some cases, be used to replace other atoms or groups besides fluorine with halogen Polyfluoroacyl fluorides and chlorides can be converted to fluoroalkyl iodides by simply heating the reactant in the presence of an alkali metal iodide [[Pg.382]

Perfluoroalkylation of substituted benzenes and heterocyclic substrates has been accomplished through thermolysis of perfluoroalkyl iodides in the presence of the appropriate aromatic compound Isomeric mixtures are often obtained W-Methylpyrrole [143] and furan [148] yield only the a-substituted products (equation 128) Imidazoles are perfluoroalkylated under LTV irradiation [149] (equation 129). 4-Perfluoroalkylimidazoles are obtained regioselectively by SET reactions of an imidazole anion with fluoroalkyl iodides or bromides under mild conditions [150] (equation 130) (for the SET mechanism, see equation 57)... 

Fluonnated ylides have also been prepared in such a way that fluonne is incorporated at the carhon P to the carbamonic carbon Vanous fluoroalkyl iodides were heated with tnphenylphosphine in the absence of solvent to form the necessary phosphonium salts Direct deprotonation with butyUithium or hthium dusopropy-lamide did not lead to yhde formation, rather, deprotonation was accomparued by loss of fluonde ion Flowever deprotonation with hydrated potassium carbonate in thoxane was successful and resulted in fluoroolefin yields of45-S0% [59] (equation 54) P-Fluorinated ylides may also be prepared by the reaction of an isopropyli-denetnphenylphosphine yhde with a perfluoroalkanoyl anhydnde The intermediate acyl phosphonium salt can undergo further reaction with methylene tnphenylphosphorane and phenyUithium to form a new yhde, which can then be used in a Wittig olefination procedure [60] (equation 55) or can react with a nucleophile [6/j such as an acetyhde to form a fluonnated enyne [62] (equation 56)... 

An analogous reaction occurs between trifluoromethyl iodide and elementary phosphorus, arsenic, antimony, sulphur or selenium (5). The experimental procedure was the same in each case, the fluoroalkyl iodide being heated in a sealed tube or autoclave with the clement in question at temperatures ranging from 170 to 280°. Table 4 shows the products of these reactions which have been isolated. 

Sulfur also reacts with fluoroalkyl mercurials and fluoroalkyl iodides to give fluorothioacyl halides. In the case of the reaction with mercurials, the halide formed is determined by substitution on the carbon attached to mercury. For example, bis(perfluoroethyl)mercury gives trifluorothioacetyl fluoride and bis-(l,l-dichloro-2,2,2-trifluoroethyl)mereury gives trifluorothioacetyl chloride. 

Reaction of elemental sulfur with fluoroalkyl iodides has not received very much attention, but it has been shown that sulfur converts 4,4-diiodoperfluoro-l-butene to pentafluoro-3-butenoyl fluoride. 

Researchers are now seeking practical ways to fluorinate the surfaces of diamond films, as the resulting surfaces are expected to have very low coefficients of friction (cf. non stick polytetrafluoroethylene or Teflon, Section 12.3) and hence have applications in low-friction tools. Direct flu-orination with elemental fluorine is impractical, but photodecomposition of fluoroalkyl iodides chemically absorbed on the diamond surface looks promising.4... 

Fluoroalkyl iodides are oxidized at the iodine atom by trifluoroperacetic acid3 7- 19 or by a mixture of trifluoroacetic anhydride with hydrogen peroxide the products are [bis(trifluoro-acetoxy)iodo]fluoroalkanes, e.g. oxidation of 1 to 2. The iodine atom oxidized in the reactions can be attached either to a nonfluorinated317 318 or a fluorinated carbon atom.319... 

Fluoroalkyl iodides are oxidized at the iodine atom by trifluoroperoxyacetic add [779, 720] or by a mixture of tnfluoroacetic anhydride and hydrogen peroxide [77iodo]alkanes are formed in almost quantitative yields [116, 117 119]... 

Several perfluoroalkyl iodides add to alkenes in the presence of 1 mol % of tetrakis(triphenylphos-phine)palladium(O) at room temperature in fair to good yields forming fluoroalkyl iodides.52 Palladium hydride elimination is less favorable than substitution of the palladium by iodide in these examples. This is due to the reaction proceeding by an unusual radical chain mechanism (equation 17). 

According to this literature survey, most investigations have been performed photochemically and in most cases, the monoadduct is composed of two isomers, the ratio of which depends upon the electrophilicity of the telogen radical. In the case of fluoroalkyl iodides, such an olefin exhibits the same reactivity towards these telogens, whatever their structure. In addition, trifluoroethylene seems less reactive than vinylidene fluoride but more reactive than hexafluoro-propene. 

Several investigations have shown that iodine transfer polymerisation can occur by emulsion or radical initiation. When emulsion initiation is chosen, a per-fluoroalkyl iodide is involved and limits the molecular weights [378,379]. This is not described here but several articles and patents from Tatemoto are sug-... 

The application of such a process allows the step by step syntheses of block copolymers either from fluoroalkyl iodides or a, >-diiodoperfluoroalkanes. Chambers investigations or those performed in our laboratory have led to the extensive use of fluoroalkyl iodides with chlorotrifluoroethylene (CTFE) for the preparation... 

The additional reaction of fluoroalkyl iodide to alkynes is important as a method of introducing fluoroalkyl groups into organic molecules. The reaction methods to emit... 

The decarbonylation of acyl chlorides or fluorides in the presence of potassium iodide is a simple one-step reaction for the preparation of fluoroalkyl iodides, e.g, formation of 2. ... 

The effect of the fluoroalkyl iodide on the telomer distribution is illustrated for CH2=CF2 in Table 7.12, as well as the effect of molar ratio of telogen to alkene and of the reaction temperature. 

Telomerisation of hexafluoropropene may be achieved using fluoroalkyl iodides as telogens [218, 219] this is rather surprising, considering that it is very difficult to achieve homopolymerisation of hexafluoropropene (Figure 7.62). It has been suggested [218] that these reactions may not be radical-chain processes but could involve successive four-centre additions of fluorocarbon iodides to the olefin (Figure 7.63). 

Dioxanes have been synthesized from l-O-allyl-l,2-diols by radical addition of per-fluoroalkyl iodides and subsequent nucleophilic cyclization.561 With sodium hydride, elimination occurs from iodides such as 1.3 other bases also give unsatisfactory results, whereas N-bromosuccinimide seems to be the reagent of choice for the cyclization to 1,4-dioxane 14. Similar results arc obtained with dibromodimethylhydantoin.561 Dihydrobenzofurans are synthesized by cyclodehydration utilizing the Vilsmeier reagent (chloromethylene)dimethylam-monium chloride is most practical.562 Nucleophilic aromatic substitution reactions with catechol derivatives also give the six-membered heterocycles.563 564 1.4-Dioxan-2-ones arc pre-... 

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