Electrochemistry represents one of the most intimate ways of interacting with molecules. This review discusses advances in synthetic organic electrochemistry since 2000. Enabling methods and synthetic applications are analyzed alongside innate advantages as well as future challenges of electroorganic chemistry.

Synthetic Organic Electrochemical Methods Since 2000: On the Verge of a Renaissance

Reductive electrosynthesis has faced long-standing challenges in applications to complex organic substrates at scale. Here, we show how decades of research in lithium-ion battery materials, electrolytes, and additives can serve as an inspiration for achieving practically scalable reductive electrosynthetic conditions for the Birch reduction. Specifically, we demonstrate that using a sacrificial anode material (magnesium or aluminum), combined with a cheap, nontoxic, and water-soluble proton source (dimethylurea), and an overcharge protectant inspired by battery technology [tris(pyrrolidino)phosphoramide] can allow for multigram-scale synthesis of pharmaceutically relevant building blocks. We show how these conditions have a very high level of functional-group tolerance relative to classical electrochemical and chemical dissolving-metal reductions. Finally, we demonstrate that the same electrochemical conditions can be applied to other dissolving metal–type reductive transformations, including McMurry couplings, reductive ketone deoxygenations, and epoxide openings.

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Scalable and safe synthetic organic electroreduction inspired by Li-ion battery chemistry

Organic electrosynthesis is an enabling and sustainable technology, which constitutes a rapidly expanding field of research. Electrochemical approaches serve as convenient and green alternatives to ...

Organic Electrosynthesis: Applications in Complex Molecule Synthesis

Recent developments in organic synthesis by electrolysis

The critical aspects of the corrosion of metal electrodes in cathodic reductions are covered. We discuss the involved mechanisms including alloying with alkali metals, cathodic etching in aqueous and aprotic media, and formation of metal hydrides and organometallics. Successful approaches that have been implemented to suppress cathodic corrosion are reviewed. We present several examples from electroorganic synthesis where the clever use of alloys instead of soft neat heavy metals and the application of protective cationic additives have allowed to successfully exploit these materials as cathodes. Because of the high overpotential for the hydrogen evolution reaction, such cathodes can contribute toward more sustainable green synthetic processes. The reported strategies expand the applications of organic electrosynthesis because a more negative regime is accessible within protic media and common metal poisons, e.g., sulfur-containing substrates, are compatible with these cathodes. The strongly diminished hydrogen evolution side reaction paves the way for more efficient reductive electroorganic conversions.

Cathodic Corrosion of Metal Electrodes-How to Prevent It in Electroorganic Synthesis.

Benzene and other aromatic compounds may be reduced to the 1,4‐dihydro‐derivatives in an undivided cell using a dispersion of hydrocarbon and aqueous quaternary ammonium hydroxide. At optimum conditions benzene is converted to 1,4‐cyclohexadiene at 90% selectivity with nearly quantitative current efficiency. A continuous reaction scheme for the benzene reduction is described.

J. P. Coleman

Papers

Reduction of Benzene and Related Compounds in Aqueous Solution and Undivided Cells