Indirect anodic fluorodesulfurization of S-aryl thiobenzoates using a triarylamine mediator

The catalytic effects of a triarylamine [(2,4-Br2C6H3)3N] (2) for the fluorodesulfurization of S-aryl thiobenzoates were investigated by cyclic voltammetry. It was found that the electron transfer from S-p-methoxyphenyl thiobenzoate to 2+ was fast while that from S-phenyl and S-p-chlorophenyl derivatives to 2+ was slow. The indirect macro-electrolysis of S-aryl thiobenzoates gave benzoyl fluoride in good yield at a less positive potential compared with direct electrolysis. A possible mechanism for triarylamine mediated fluorodesulfurization was proposed.