Electrofluorination, selective organic

Selective Organic Electrofluorination. The electrogeneration of fluorine from the electrolysis of a mixture of KF and HF has been well known for many decades. Organic perfluorination using HF and HF/KF is used widely. Now the use of HF complexes with tetraalkylammonium fluoride has led to the anodic difluorination of dithioacetals. 

In a recent review, Tao etal. [34] describe the partial fluorination and the perfluorination of organics with particular emphasis on medically important compounds and pharmaceuticals. The selective electrofluorination (SEF) of olefins and active methylene groups is reviewed by Noel et al. [35] In the case of heterocycles, nuclear fluorination is known to be the predominant process. However, in aromatic compounds, nuclear substitution as well as addition proceeds simultaneously, leading to the formation of a mixture of products. The influence of solvents, supporting electrolytes, and adsorption on product yield and selectivity is summarized and evaluated. Dimethoxyethane is found to be a superior solvent for SEF processes. Redox mediators have been employed to minimize anode passivation and to achieve better current efficiencies. 

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