Fluorosulfonic add

Pure fluorosulfonic add does not attack glass. It reacts explosively with water and fumes in airt and it rapidly destroys cork and rubber. It decomposes in the presence of benzene and chloroform, splitting off hydrogen fluoride with ether, a strongly exothermic reaction causes the formation of ethyl acetate. The fluoro add vapor itself is stable to about 900°C. 

Nitrosyl hydrogen sulfate adds to aikenes at -40 C in liquid SO , in Markovnikov fashion giving 2-sulfato-oximes (37-84%).Reactions of nitrogen oxides with aikenes are usually complex, yet some have limited industrial, rather than laboratory, importance. Nitryl tetrafluoroborate in acetic anhydride at -65 to -45 C adds Markovnikov fashion to aikenes, with only fair stereoselectivity, giving 3-ni-troacetates in 36-40% yields. Nitryl fluorosulfonate adds to perfluoroalkenes in fluorosulfonic acid/ffeon-113 giving 63-92% 0-nitroperfluoroalkyl fluorosulfonates. 

The controlled potential electrolysis of cyclohexane carried out at 1.8S V in fluorosulfonic add containing 1.15 M acetic acid yields an a,P-unsaturated ketone as a single product in 30% current yield. 

Nitronium fluorosulfate in fluorosulfonic acid adds electrophilically across the double bond offluoroolefins in a nonspecific manner. Tnfluorochloroethylene reacts accordingly with nitronium fluorosulfate to give a 2.1 mixture of regio-isomers [7] (equation 7). Under these reaction conditions perfluoropropylene is unreactive even after extended heating at 80 C 2-Nitroperfluoropropyl fluorosulfate is obtained on treatment of the perfluoropropylene with nitronium fluorosulfate in antimony pentafluoride [5] (equation 8). 

An extensive study on the use of benzothiazoles as carbonyl equivalents has been conducted (78TL5, 9). The 2-lithiobenzothiazole (576) readily adds to carbonyl compounds to furnish on dehydration of the carbinol a vinylbenzothiazole (578). The benzothiazole nucleus can then be unmasked by a sequence of reactions involving (a) Af-methylation with methyl fluorosulfonate, (b) addition of either hydride (NaBKU) or an organometallic (MeLi) to afford the iV-methylbenzothiazoline and (c) hydrolysis of the crude Af-methylbenzothiazo-line (e.g. AgN03). A representative example is shown in Scheme 126. 

HFP and higher terminal fluoroolefins add H0S02F only at elevated temperature [6] to give the corresponding a,a-difluoroethers of fluorosulfonic acid ... 

In the polymerization of monocyclic ethers initiated with super adds such as methyl fluorosulfonate and methyl trifluoromethanesulfonate, two kinds of propagating species are observed in the reaction system and an extensive kinetic study has been done for the polymerization of THF, Eq. (6)185). However, the kinetic study of the polymerization of bicyclic ethers with super acid has not been reported. 

The action of a Zn/Cu couple on 1,3-dibromo ketones and secondary amides yields 2-dialkylamino-1,3-dioxolanes (451 equation 208). Fluorosulfonic peracid anhydride adds to trifluoroacetonitrile to give an amide acetal (452 equation 209). In the addition of (Z)-2-butene-l,4-diol to trichloroacetoni-trile, catalyzed by sodium, the 1,3-dioxepin (453 equation 210) is produced. Bicyclic amide acetals (454 equation 211) are byproducts in the reaction of lactim ethers with diketene. TTie methyl esters of perfluorinated carboxylic acids react with diethanolamine to afford bicyclic amide acetals (455 equation 212). Heating of maleic anilides (456 equation 213) with acetic acid anhydride/sodium acetate gives heterocyclic compounds (457) containing an amide acetal structure. ... 

Cyclodehydration Aluminum chloride see also Methyl fluorene-9-carboxylate). Dowtherm. Fluorosulfonic acid. Hydrogen fluoride. Perchloric add. Phosphorus pentoxide. Phosphoryl chloride. Polyphosphate ester. Polyphosphoric add. Potassium bisulfate. Sodium aluminum chloride. Sulfur trioxide-Dimelhylformamide. />-Toluenesulfonic acid. Trifluoroacetic acid. Trifluoroacetic anhydride. 

In reactions not possible with the second-row-element-containing pyrrole and furan, thiophene sulfur can add electrophilic species. Thiophenium salts though not formed efficiently from thiophene itself, are produced in high yields with polyalkyl-substituted thiophenes. The sulfur in such salts is probably tetrahedral, i.e. the sulfur is sp hybridised (CAUTION Methyl fluorosulfonate is highly toxic). 

As far as the reaction mechanism is concerned, we assume that the sequence conunences with the addition of the Lewis add to the carbon atom of the phosphaalkyne (9 - 69), in accord with the polarization of the PsC bond [10b]. The addition of fluorosulfonic acid to 9 a in liquid SO2 also begins with C-protonation [63]. The resultant, activated phosphaal-kenes undergo [2 -1- 2]-cycloaddition with a second equivalent of 9 to furnish the adducts 70. A subsequent [2 -I-1]-cycloaddition with a third equivalent of 9 is then responsible for the formation of the spirocyclic phosphorus derivatives (- 71). 

At temperatures above — 60°C, the C-protonated ketodiazonium ion 2.13 is formed preferentially. N2 is eliminated rapidly and the resulting carbenium ion adds to FSOf forming a fluorosulfonate (Wentrup and Dahn, 1970). 

This type of initiation is limited by the nucleophiUcity of the anion A derived from the acid. For acids other than the very strong adds such as fluorosulfonic and triflic acids, the anion is sufficiently nucleophilic to compete with monomer for either the proton or secondary and tertiary oxonium ions. Only very-low-molecular-weight products are possible. The presence of water can also directly disrupt the polymerization since its nucleophilicity allows it to compete with monomer for the oxottium ions. 

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