Perchloryl fluoride fluorination

In general, examples of substitution of sodium and potassium in organometallic derivatives by fluorine are limited to the salts of active methylene compounds. Their fluorination is achieved with perchloryl fluoride.fluorine, N-F reagents. " and xenon difluoride " (Table 10). The fluorination of metal enolates is discussed under metal-assisted substitution ot... 

The full paper on the synthesis of 14 -fluoro-steroids by perchloryl fluoride fluorination of A -17-acetates has now appeared. It has been shown that 16a-bromoacetoxyprogesterone alkylates cysteine, histidine, methionine, lysine, and /5-mercaptoethanol under physiological conditions. 

The perchloryl fluoride [7616-94-6] FCIO, the acyl fluoride of perchloric acid, is a stable compound. Normally a gas having a melting poiat of —147.7° C and a boiling poiat of —46.7°C, it can be prepared by electrolysis of a saturated solution of sodium perchlorate ia anhydrous hydrofluoric acid. Some of its uses are as an effective fluorinating agent, as an oxidant ia rocket fuels, and as a gaseous dielectric for transformers (69). 

Synthetic procedures are available for the preparation of fluoro, chloro, bromo and iodo compounds from the corresponding lithio derivatives. Perchloryl fluoride (FCIO3), N-chlorosuccinimide, bromine and iodine are examples of reagents which can be used to introduce fluorine, chlorine, bromine and iodine, respectively. 

The enamines, enol ethers and enol acetates of A -3-keto steroids provide important substrates for fluorination with FCIO3. Reaction of such A -enol ethers and acetates (6) with perchloryl fluoride results in 6a- and 6jff-fluoro-A -3-ketones (7) and (8), the latter representing the more abundant isomer. Tetrahydrofuran or dioxane-water mixtures appear to be particu-... 

It is more reactive than perchloryl fluoride and therefore not without danger. It forms, for instance, a highly explosive product with pyridine. Like perchloryl fluoride it reacts with enol ethers, esters and enamines, but at lower temperature (—78°) to yield the fluorinated ketones as well as addition... 

The fluonnation of both mono and dinitro enolates proceeds well with perchloryl fluoride. The mononitro fluorinated intermediates have been used to develop fluorinated materials of general synthetic utility [III, 113] (equation 63)... 

Enamines from steroidal ketones have been fluorinated by means of perchloryl fluoride (119,120) to give the a-fluorinated ketones. Theenamino ketone (49) was brominated to give a salt from which the bromoenamino ketone (175) was isolated on treatment with dilute carbonate solution (121). 

The final route to fluorine compounds is electrofluorination (anodic fluorination) usually in anhydrous or aqueous HF. The preparation of NF tFl3 j (x = 1, 2, 3) has already been described (p. 818). Likewise a reliable route to OF2 is the electrolysis of 80% FIF in the presence of dissolved MF (p. 638). Perchloryl fluoride has been made by electrolysing NaC104 in FIF but a simpler route (p. 879) is the direct reaction of a perchlorate with fluorosulfuric acid ... 

P10.2 Given the following molecular data for perchloryl fluoride. (Perchloryl fluoride (CIO3F) is tetrahedral with three oxygens and a fluorine bonded to a central chlorine. ... 

Fluorination of the ester with perchloryl fluoride by an established method led to... 

There is a danger of explosion during replacement of a lithium substituent by fluorine using perchloryl fluoride. 

Copper(II) sulfate Cumene hydroperoxide Cyanides Cyclohexanol Cyclohexanone Decaborane-14 Diazomethane 1,1-Dichloroethylene Dimethylformamide Hydroxylamine, magnesium Acids (inorganic or organic) Acids, water or steam, fluorine, magnesium, nitric acid and nitrates, nitrites Oxidants Hydrogen peroxide, nitric acid Dimethyl sulfoxide, ethers, halocarbons Alkali metals, calcium sulfate Air, chlorotrifluoroethylene, ozone, perchloryl fluoride Halocarbons, inorganic and organic nitrates, bromine, chromium(VI) oxide, aluminum trimethyl, phosphorus trioxide... 

Bromine bromate, 0276 Bromine dioxide, 0258 Bromine perchlorate, 0235 Bromine trioxide, 0259 Bromyl fluoride, 0239 Chlorine dioxide, 4042 Chlorine perchlorate, 4101 Chlorine trifluoride oxide, 3982 Chlorine trioxide, 4044 Chloryl hypofluorite, 3973 Chloryl perchlorate, 4104 Dichlorine oxide, 4095 Dichlorine trioxide, 4100 Dicyanogen AW -dioxidc. 0998 Dioxygen difluoride, 4320 Fluorine perchlorate, 3976 Hexaoxygen difluoride, 4327 Iodine dioxide trifluoride, 4334 Iodine(V) oxide, 4627 Iodine(VII) oxide, 4628 Oxygen difluoride, 4317 Perbromyl fluoride, 0240 Perchloryl fluoride, 3974... 

The highest yield of perchloryl fluoride (97%) was achieved with a mixture of fluorosulfonic acid and SbFj as fluorinating medium. Potassium, sodium, lithium, magnesium, barium, calcium, and silver perchlorates and perchloric acid itself undergo the reaction. Commercial reagents are used and their additional puriflcation is not necessary unlike all the previous methods the preparation of perchloryl fluoride by this method can be carried out at room temperature. At high temperature (100°-135°C) the reaction time is 1-10 min in all, which allows the process to be carried out continuously in a packed column. The purity of product obtained after the usual puriflcation reaches 98% and over air and carbon dioxide are present as trace impurities 23). 

R.E. Ehrenkaufer, R.R. MacGregor, Synthesis of [ F]-perchloryl fluoride and its reactions with functionalized aryllithiums, Int. J. Appl. Radiat. Isot. 34(1983)613-615. R. Chirakal, G. Firnau, J.G. Schrobilgen, J. McKay, E.S. Garnett, The synthesis of [ F]xenon difluoride from [ F]fluorine gas, Int. J. Appl. Radiat. Isot. 35 (1984) 401-404. 

S. Nakanishi, R.L. Morgan, E.V. Jensen, 4-Fluorinated steroids from the reaction of perchloryl fluoride with steroid enamines, Chem. Ind. (London) (1960) 1136-1137. 

Fluorination of sulfonamides 147 and 148 takes place upon deprotonation with NaH and reaction with perchloryl fluoride, FCIO3, to give products 149 and 150 (Scheme 19) <2000JOC7583, 2000CPB1954>. The resulting A-fluorosultams 149 and 150 have been used for the asymmetric fluorination of aryl ketone enolates (vide infra). 

Introduction of Fluorine with Perchloryl Fluoride (FC103)... 

Perchloryl fluoride generally reacts with electron-rich alkencs or with various carbanionie substrates (Scheme 1), where salts are usually prepared in situ and further react at low temperature or in some cases at room temperature temperature control must be taken into account. However. it has been pointed out several times that serious explosions may occur and for this reason the reactions are potentially hazardous and safety precautions must be taken when working with this reagent. Over the last twenty years fluorination reactions with perchloryl fluoride have been partially discussed in several monographs6 8 and review papers.9 12... 

Takeuchi and co-workers5 have recently prepared a number of a-fluorocarboxylic acid derivatives 1 and 2 and it is very interesting that they emphasized that no explosion occurred in more than 200 fluorinations performed 17 however, they recommend the use of perchloryl fluoride diluted with nitrogen and synthesized in the laboratory. 

A number of cycloalkyl-, vinyl-, aryl-, and benzyllithium compounds (predominantly benzyl-lithiums) are converted into fluoro derivatives in good to excellent yields, e.g. formation of 4, 5, and 6 19 however, when this method was applied to the synthesisof 3-fluorobenzocyclobutene from the lithium salt a violent explosion occurred when the reaction mixture was warmed from — 70 C to room temperature.20 Various fluoro-substituted thiophenes 7 are obtained when the starting compounds (thiophene, 2-methylthiophene, etc.) arc transformed with al-kyllithium compounds to the corresponding lithium derivatives then fluorinated with perchloryl fluoride at 0 C.21 Potassium tricyanomethanidc is converted at —15 C in triglyme into tricyanofluoromethane in 81 % yield.22... 

Various /i-oxo esters are fluorinated by perchloryl fluoride in the presence of sodium ethoxide, while the fluoro products 8 are usually converted into a-fluoro esters 9 various saturated and unsaturated long-chain esters, e.g. 10 and 11, can be prepared in high yield.23-24... 

Various steroids are fluorinated by conversion into the enolates, followed by fluorination with perchloryl fluoride to give the 16-fluorinated products 16.19 28 The Schiff base of 7-aminodeacetoxyeephalosporanic acid tart-butyl ester is converted into an anion with potassium tm-butoxide,29 while further reaction with perchloryl fluoride diluted with nitrogen at — 50 C gives 7-(benzylideneamino)-7-fluorodeacetoxycephalosporanicacid fer/-butyl ester (17) in high yield. An attempt to prepare 2-fluoropodophyllotoxin by reaction of the enolate with perchloryl fluoride resulted in a violent explosion.30... 

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