Current approaches to the electrochemical synthesis of organo-fluorine compounds

Recent trends in the synthesis of organo-fluorine compounds using the conventional selective electrochemical fluorination (SEF) route as well as other novel synthetic approaches are presented. In the conventional SEF route, fluorinations of the active methylene group in the side chain as well as unsaturated alkenes have been achieved. In the case of heterocycles, nuclear fluorination is the predominant process. 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 has also been evaluated in recent studies. DME is found to be a superior solvent for the above processes. In the SEF process itself, redox mediators have been employed to minimize passivation and achieve better current efficiencies. Nitrogen bases containing perfluoro alkyl unit have been synthesized using redox catalysts as mediators and trifluoromethylation was achieved by the sacrificial anode technique. The introduction of the trimethyl silyl (TMS) group into the ACF3 moiety to form very reactive ACF2–TMS synthon, leads to the synthesis of interesting organic molecules. A brief summary of important biologically active fluoro organic molecules that have been prepared by the electrochemical route is also provided