A guide to organic electroreduction using sacrificial anodes

Abstract

This review focuses on recent advances in sacrificial anode-enabled organic electroreductions.

Improving the Mg Sacrificial Anode in Tetrahydrofuran for Synthetic Electrochemistry by Tailoring Electrolyte Composition

“…Here, we investigate the effect of supporting electrolytes on Mg stripping with the aim of improving Mg sacrificial anode performance in tetrahydrofuran (THF)-based electrolyte. Currently, the most commonly employed solvent for systems using Mg sacrificial anodes is dimethylformamide (DMF) . However, the evident solvent limitation could pose challenges when attempting to broaden the application of reductive electrosynthesis to different types of organic transformations.…”

Nickel‐Electrocatalyzed Synthesis of Bifuran‐Based Monomers

“…[50,56] Commonly, electrolysis has been conducted using nickel, [48,49,[51][52][53][54][56][57][58][59] gold, [50] and graphite/carbon nanotube [55] cathodes with sacrificial anodes such as iron, [49,51,54,58] duralumin, [49] stainless steel, [48,59] magnesium, [50] zinc, [51][52][53][54] nickel, [56] or Fe 64 Ni 36 . [57] While sacrificial anodes offer some benefits in organic electrosynthesis, [60,61] the dissolution of the anode can complicate electrolysis, altering the inter-electrode gap as reaction progresses, [62] and the generation of stoichiometric metal waste can complicate waste disposal on a larger scale. [63] A few methods in the literature have avoided the use of sacrificial anodes in nickel-mediated electrohomocouplings by utilizing water [56] and urea oxidations [64] as counter-reactions in a divided cell.…”

Convergent paired electrolysis for zinc-mediated diastereoselective cinnamylation of α-amino esters

“…(entries 8 and 9). 11 The reaction was sensitive to the type of additive salt used, with KPF 6 preventing reaction progress, while LiClO 4 resulted in a 37% yield (entries 10 and 11). The use of n BuClO 4 was also found to be ineffective (35%, entry 12).…”

“…Electrosynthesis has gained popularity due to its tunable reactivity and absence of exogenous oxidants/reductants, leading to the advancement of new transformations through in situ reactive intermediate generation. 6,7 In the 1990s, organic electrochemistry progressed, including the synthesis of organozinc reagents through the reduction of zinc ions from a sacrificial zinc anode. 8 The formation of organozinc species is achieved through the application of electricity, which dissolves zinc ions, resulting in species capable of reacting with electrophiles like aldehydes, ketones, and imines.…”