Electrolytic partial fluorination of organic compounds. Part 65: Regioselective anodic difluorination of oxazolyl sulfides

Electrochemical fluorination of 2-alkylthio-4-methyloxazoles has been successfully carried out using Et4NF.nHF (n=4, 5) as the supporting electrolyte and fluoride source to provide the corresponding 2-alkylthio-4,5-difluoro-4-methyl-2-oxazolines, and fluorination did not take place at alpha to the sulfur atom. In the case of electrochemical fluorination of 2-methylthio-4-cabomethoxyoxazole afforded a 2,5-difluoro-3-oxazoline derivative in addition to a 4,5-difluoro-2-oxazoline one. In contrast, anodic fluorination of 2,4,5-trimethyloxazole devoid of a thio group resulted in no formation of fluorinated products. (C) 2002 Elsevier Science Ltd. All rights reserved.