Achieving advances in the development of clean and efficient synthetic routes has become an important aim in research. In recent years, the search for new sustainable methodologies, notably environmentally benign synthetic procedures, has gained the attention of the scientific community. Electrosynthesis is a tool that has been extensively studied due to its potential application in chemical transformations and it adheres to the principles of green chemistry. Organochalogen compounds form an important class of molecules, since many of them have properties that can be applied in medicine and materials science. Thus, herein we provide a comprehensive and updated overview covering recent advances in the electrochemical C(sp2)−H bond chalcogenation of activated arenes and heterocycles as well as electrochemical chalcogenation through oxidative cross‐coupling reactions and chalcogen‐functionalization of alkenes/alkynes. The scope, limitations, and mechanisms are described and discussed, detailing the fundamental aspects and benefits of electrochemistry for the chalcogenation of organic compounds. The content of this Minireview demonstrates that it is possible to provide new synthetic routes and to improve the existing methodologies, to obtain processes more in line with current environmental protection aims. The reader will also find a discussion on the fundamental aspects and benefits of applying electrosynthesis to the assembly and operation of an electrolytic cell.
Herein, we report an electrochemical oxidative C(sp2)–H selenylation of activated arenes. The reaction proceeds in an undivided electrochemical cell at Pt‐electrodes in the presence of KI as the supporting electrolyte, which could suffer oxidation at the anode. Using this benign, atom‐economic protocol, the desired selenylated products were obtained regioselectively in good to excellent yields by using a half molar equiv. of the diselenides.
The Cover Feature shows a city skyline which represents the modernization of the synthetic methods, while the cyclic voltammogram represents the redox activity of the species involved in the reaction. We propose a new electrochemical oxidative assessment for C(sp2)–H selenylation using Pt electrodes, and two mechanistic pathways. Path A: Activated arenes in the presence of KI as electrolyte can provide iodinated aromatic derivatives as intermediaries. Path B: Diselenides in the presence of KI may provide PhSeI as an electrophilic species. Selenylated products were obtained with good to excellent yields. Artwork by Vinicius F. Pereira, coauthor of this paper. More information can be found in the Communication by A. L. Braga, S. R. Mendes et al.
The Cover Feature represents, in the background, an electrochemical reaction system with electrodes and energy source. The cover describes the main reaction conditions discussed in this Review, such as different electrodes, electrolytes, heterocycles, chalcogens, solvents, current and time. More information can be found in the Minireview by G. M. Martins et al. on page 5928 in Issue 24, 2019 (DOI: 10.1002/celc.201901525).
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