Yk. Hou et T. Fuchigami, Electrolytic partial fluorination of organic compounds - XL. Solvent effects on anodic fluorination of heterocyclic sulfides, J ELCHEM SO, 147(12), 2000, pp. 4567-4572
Solvent effects on electrolytic partial fluorination of alpha-(2-benzoxazol
ylthio)-. alpha-(2-benzothiazolylthio)-, and alpha-(2-pyrimidylthio)acetate
s were investigated systematically using acetontrile (MeCN) and 1,2-dimetho
xyethane (DME) containing Et4NF . nHF (n = 3, 4) as a supporting electrolyt
e and a fluoride ion source. MeCN was not suitable for the fluorination of
these heterocyclic sulfides since formation of nonconductive polymers on th
e anode took place to result in low yields or no fluorination of fluorinate
d products. In contrast, the use of DME did nor cause such polymer film for
mation and provided much better or excellent fluorinated product yields. Th
e superiority of DME can be explained in terms of its ability to solvate th
e cationic part of the fluoride salt in which a reactive fluoride ion is le
ft for easy attack on the anodically generated cationic intermediate. It is
noted that addition of DME into MeCN electrolytic solution markedly increa
sed the product yield and current efficiency since the polymer film formati
on on the anode and overoxidation of the fluorinated products were effectiv
ely suppressed. (C) 2000 The Electrochemical Society. S0013-4651(99)09-017-
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