Selective anodic fluorination other

Generally, anodic benzylic substitution reactions take place readily. However, anodic benzylic fluorination does not always occur. The major competitive reaction is acet-amidation when MeCN is used as a solvent [24-26]. In contrast to these cases, triphenylmethane is selectively monofluorinated in 80% yield [27]. When Et4NF-/7HF n = 3,4,5) is used in the absence of MeCN, anodic fluorination of toluene and mono-fluoromethylbenzene provides mainly mono- and difluoromethylbenzenes, respectively [22]. On the other hand, difluoromethylbenzene affords only products fluorinated in the benzene ring [Eq. (4)] [28]. 

Solvent-free electrochemical fluorination is an alternative method for preventing anode passivation and acetoamidation [18, 19]. As already mentioned, handling extremely corrosive and poisonous anhydrous HF in a laboratory setting is accompanied by serious hazards and experimental difficulties. Molten salts such as 70 % HF/pyridine (Olah s reagent) and commercially available EtaN-SHF [20] are often used to replace anhydrous HF. Other molten salts with the general formula R4NF-nHF (n > 3.5, R = Me, Et, and n-Pr) are useful in selective electrochemical fluorination. These electrolytes... 

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