Sulfonyl chloride as a disposable electron withdrawing substituent in halex fluorinations
Syntheses of 1,3-difluorobenzene and 2,6-difluorotoluene are described via chlorosulfonation, catalytic Halex-fluorination, and desulfination of 1,3-dichlorobenzene and 2,6-dichlorotoluene.
Tetraphenylphosphonium bromide-catalyzed 'Halex' fluorination of chloroaryl sulfonyl chlorides
Halogen-exchange of chloroaryl sulfonylchloride derivatives with spray-dried potassium fluoride was found to proceed efficiently by employing tetraphenylphosphonium bromide as a catalyst.Subsequent desulfonylation of the fluoroaryl sulfonyl derivatives readily afforded fluoroaromatics under acidic condition.