Electrosynthesis offers a powerful tool for the formation of anion and cation radical intermediates and for driving clean synthetic reactions without the need for additional chemical reagents.

This article provides an outline of recent studies on selective electrochemical fluorination in ionic liquid fluoride salts toward green sustainable chemistry. First, a brief historical background of electrochemical fluorination in organic solvents is provided, and some particular problems and unique solvent effects associated with this technique are briefly mentioned. Second, recent progress in selective fluorination and fluorodesulfurization of organic molecules and macromolecules in ionic liquids using direct and indirect electrolysis with recyclable mediators is reviewed.

In this paper, we report a novel electrochemical doping method for conducting polymer films based on bipolar electrochemistry. The electrochemical doping of conducting polymers such as poly(3-methylthiophene) (PMT), poly(3,4-ethylenedioxythiophene) (PEDOT), and poly(aniline) (PANI) on a bipolar electrode having a potential gradient on its surface successfully created gradually doped materials. In the case of PEDOT film, the color change at the anodic side was also observed to be gradually transparent. PANI film treated by the bipolar doping gave a multicolored gradation across the film. The results of UV-vis and energy dispersive X-ray analyses for the doped films supported the distribution of dopants in the polymer films reflecting the potential gradient on the bipolar electrode. Furthermore, the reversibility of the bipolar doping of the PMT film was demonstrated by a spectroelectrochemical investigation.

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Metrics & MoreArticle Recommendations CONSPECTUS: Organofluorine compounds are key materials applied in daily life because of their versatile utility as functional materials, pharmaceuticals, and agrochemicals. Development of the selective fluorination of organic molecules under safe conditions is therefore one of the most important subjects in modern synthetic organofluorine chemistry. Thus, various electrophilic fluorination reagents such as XeF 2 , (PhSO 2 ) 2 NF (NFSI), Et 2 NSF 3 (DAST), (MeOCH 2 CH 2 ) 2 NSF 3 (Deoxofluor), 1-chloromethyl-4-fluoro-1,4-diazoniabicyclo-[2.2.2]octane bis-(tetrafluoroborate) (Selectfluor), N-fluoropyridinium salts, and 4-tertbutyl-2,6-dimethylphenylsulfur trifluoride (Fluolead) have been developed for chemical fluorination to date and the development of new fluorinating reagents is still ongoing.Electrochemical synthesis has recently attracted much attention from the perspective of green sustainable chemistry because no hazardous reagents are required and scale-up is generally easy. Although electrochemical perfluorination of organic compounds using a nickel anode in anhydrous HF has been well-established to manufacture perfluoro-functional materials, electrochemical partial fluorination (selective electrochemical fluorination) has been underdeveloped due to the low nucleophilicity of fluoride ions and anode passivation, which interferes with electrolysis. Selective electrochemical fluorination can be commonly achieved in aprotic solvents containing fluoride ions to provide mostly mono-and difluorinated products. Electrolysis is conducted at constant potentials slightly higher than the first oxidation potential of a substrate. Constant current electrolysis is also effective for selective fluorination in many cases. Choice of the combination of a supporting fluoride salt and an electrolytic solvent is most important to accomplish efficient selective fluorination.In this Account, we focus on our recent work on the electrochemical mono-and difluorination of various organic compounds and their synthetic application. We first briefly explain our research background of electrochemical fluorination. Main factors such as the effects of fluoride salts as supporting electrolytes, electrolytic solvents, and anode materials on the selectivity and efficiency of fluorination are discussed. Next, effects of PEG oligomer additives enhancing the nucleophilicity of fluoride ions and organic solventfree systems using poly(HF) salt ionic liquids as well as recyclable mediatory systems for electrochemical fluorination are described.The desulfurizative monofluorination of xanthate and gem-difluorination of benzothioate and dithioacetals are briefly mentioned.Regioselective anodic fluorination of various heterocyclic compounds having a phenylthio group as electroauxiliary and heterocycles containing sulfur and other heteroatoms are also described. In addition, a boryl group is shown to be a good leaving group for anodic fluorination. Moreover, electrochemically α,α-difluorinated phenylsulfides and ph...

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Self-supported electrochemical methoxylation and acetoxylation of various organic molecules were carried out using a thin-layer flow cell without intentionally added supporting electrolyte. The thin-layer flow cell employed in this work had a simple geometry with working and auxiliary electrodes directly facing each other with 80 m distance. Controlling factors for these kinds of self-supported electrochemical methoxylation and acetoxylation, such as the electrode material, the current density, and the flow rate were optimized to allow moderate to high yields of the corresponding methoxylated and acetoxylated products to be achieved in single flow-through operations.