Ethyl fluorosulfonate

While attempting to prepare an T71-(vinylcarbene)iron complex121 by the alkylation or acylation of an a,/3-unsaturated acylferrate, Mitsudo and Wa-tanabe found122 that the major isolated product was in fact an -vinylketene complex (178), formed presumably by the carbonylation of an intermediate V-vinylcarbene, which may then undergo olefin coordination to the vacant metal site. All attempts to isolate such intermediates, or to observe them by 13C NMR spectroscopy, failed. Only in the reaction between potassium tetracarbonyl -cinnamoy ferrate (179.a) and pivaloyl chloride (180.b) was a side product (181) isolated in appreciable yield. In other reactions, only a trace (<1%) of such a compound was detected by spectroscopy. The bis(triphenylphosphine)iminium(l + ) (PPN) salts of 179.a and 179.b also reacted with 2 equiv of ethyl fluorosulfonate to give 178.g and 178.h in 21 and 37% yield, respectively. All products were somewhat unstable to silica gel, hence the low isolated yields in some cases. 

Two equivalents of ethyl fluorosulfonate must be used (one ethylates the triflu-oroacetate ion) to avoid complications arising from ethylation of ether oxygens in the tetraglyme solvent. The product must be distilled out of the reaction mixture on a vacuum line within 5 min after addition is complete. The hydri-... 

The hydroxyl group of ethyl 2-hydroxy-4-oxo-4//-pyrimido[2,l-a]-isoquinoline-3-carboxylate (20) was methylated with methyl iodide in dry boiling acetone for 5 h in the presence of potassium carbonate, with dimethyl sulfate in methylene chloride in methanol in the presence of Triton B at 20°C for 18 h, with methyl fluorosulfonate in 2.5 M sodium hydroxide at 20°C for 5 h, and with diazomethane in a mixture of diethyl ether and methylene chloride at 20°C for 3 h to give the 2-methoxy derivative (89AJC2161). The hydroxy group of 3-hydroxymethyl-4//-pyrimido[2,l-b]-isoquinolin-4-one was alkylated and acylated with 2-(diethylamino)ethyl chloride in dimethylformamide in the presence of sodium hydroxide, and with acetic anhydride in boiling chloroform in the presence of triethylamine and a few drops of 4-dimethylaminopyridine, respectively (86EUP 166439). 

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. 

The N-alkylation can be carried out with or without a solvent, using alkyl halides, tosylates, sulfates, phosphates, and for difficult cases the very powerful but extremely toxic methyl fluorosulfonate. Excess methyl and ethyl iodides are convenient solvents longer chain alkyl halides often are used with chloroform or tetrachloroethane as solvents. Ketones such as acetone and butanone have been used, and higher acyclic and alicyclic ketones have been claimed18 to give high yields of substantially pure salts. 

Fig. 26. Correlation of relative proton affinities of pyridines (APA) with their solution nucleophilicities (N) toward methyl fluorosulfonate in 2-nitropropane at 25°C (squares) and ethyl iodide in nitrobenzene at 60°C (circles) (8IJOC635).

Uans-a-Methoxystilbene. The enol of desoxybenzoin (1) is predominately 0-m ethylated by methyl fluorosulfonate in HMPT ... 

Colorless liquid, completely stable up to 900°C. Reacts explosively with water. Fumes in air. At room temperature does not attack S, C, Se, Te, Pb, Ag, Cu, Zn, Fe, Cr or Mn, but does react with Sn with mild evolution of gas. Mercury is also slightly attacked. Rubber, cork and sealing wax are rapidly destroyed. Vigorously attacks S, Pb, Sn and Hg at higher temperatures. Reacts exothermically with acetone to give a dark red-brown color (color test for fluorosulfonic acid). Reacts with benzene and chloroform, splitting off HF. Ether reacts exothermically and with effervescence to form the ethyl ester. If pure, does not attack glass. 

Though it requires vigorous conditions and is less common than nucleophilic epoxidation, electrophilic epoxidation of aperfluoroalkene is possible with the potent combination of chromic oxide and fluorosulfonic acid, providing another route to hexafluoropropylene oxide (1). As a further example of electrophilic attack, hexa-fluoro Dewar benzene (3) is transformed into either a mono- or a diepoxide by the powerful hypofluorous acid-acetonitrile complex.The fact that the much weaker electrophile MCPBA readily epoxides such electron-deficient alkenes as ethyl pentafiuoromethacrylate (4) suggests that it actually reacts via nucleophilic attack at the [3-carbon. 

Ammonia Dibutyltin maleate Dibutyltin oxide Fluorosulfonic acid Phosphine Sodium ethylate Sodium hydride Tetrabutyl titanate Tetraisopropyl titanate p-Toluene sulfonic acid Zirconium butoxide catalyst, condensation reactions Dibutyltin diacetate Piperidine catalyst, conductive polymers Iron (III) toluenesulfonate catalyst, conversion of acetylene to acetaldehyde Mercury sulfate (ic) catalyst, copolymerization Di butyl ether catalyst, cracking Zeolite synthetic... 

Ethyl 2,3-diphenyl-2,3-dihydroxybutyrate treated with fluorosulfonic acid at 0°... 

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