Paired Electrochemical Reactions and the On‐Site Generation of a Chemical Reagent

Abstract

While the majority of reported paired electrochemical reactions involve carefully matched cathodic and anodic reactions,t he precise matching of half reactions in an electrolysis cell is not generally necessary.D uring ac onstant current electrolysis almost any oxidation and reduction reaction can be paired, and in the presented work we capitalize on this observation by examining the coupling of anodic oxidation reactions with the production of hydrogen gas for use as ar eagent in remote,P d-catalyzed hydrogenation and hydrogenolysis reactions.T ot his end, an alcohol oxidation, an oxidative condensation, intramolecular anodic olefin coupling reactions,anamide oxidation, and amediated oxidation were all shown to be compatible with the generation and use of hydrogen gas at the cathode.T his pairing of an electrolysis reaction with the production of achemical reagent or substrate has the potential to greatly expand the use of more energy efficient paired electrochemical reactions.Paired electrochemical reactions that produce desirable products at both the anode and cathode are frequently put forth as am ethod for optimizing the energy efficiency of oxidation and reduction reactions, [1][2][3] and there are outstanding examples of their utility. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] Fore xample,t he chloro-alkali process that generates sodium hydroxide (reduction of water at the cathode) and chlorine gas (oxidation of chloride at the anode) from sea water is currently conducted on amassive scale. [19] Many other efforts have been dedicated as well, particularly in the general area of energy conversion. [20][21][22][23][24][25][26][27][28][29] However,inspite of the potential paired electrochemical reactions hold for running more sustainable processes and the impressive examples illustrating this potential, the technique remains primarily of interest to chemists specifically engaged in the development of new electrochemical methods.A number of factors contribute to this situation. These factors range from little need to consider the energy efficiencyo f synthetic methods conducted in an academic laboratory setting to the impression that paired electrochemical reactions require "carefully matched" oxidation and reduction reactions and hence have limited synthetic generality.W ith respect to the first point, academic chemists are becoming increasingly aware of the need for more sustainable synthetic methods and strategies.I nt hat context, it makes sense to examine methods that meet the challenge from both ap erspective of atom and energy economy.P aired electrolysis reactions offer such an opportunity.T he second point raised above represents ap otentially more significant barrier. If paired electrochemical reactions really do require "carefully matched" oxidation and reduction reactions that limit the generality of the products that can be made,t hen interest in the reaction among the synthetic community will be equally limited. Fortunately,the perception that paired electrochemical reactions require...

Radical–Radical Cross-Coupling Assisted N–S Bond Formation Using Alternating Current Protocol

“…In recent years, chemists have turned their attention to develop convergent paired electrolysis, in which both oxidation and reduction processes synergistically produce the target product. 14 Although this method is theoretically promising and energy-efficient, the convergent paired electrolysis (Figure 1C) still remains largely under-developed, [15][16][17] probably because of the lower yield due to the conflict between slow interelectrode mass transport rate and short survival time of intermediates.…”

Merging Electrolysis and Nickel Catalysis in Redox Neutral Cross-Coupling Reactions: Experiment and Computation for Electrochemically Induced C–P and C–Se Bonds Formation

“…6 In contrast, paired electrolysis is a more attractive method in which the half-reactions at both anode and cathode contribute simultaneously to the formation of the desired products, thus improving the atom economy and energy efficiency of the catalytic process. [34][35][36][37][38][39][40][41][42][43] Typically, there are three main types of paired electrolysis, namely, parallel-, sequential-, and convergent paired electrolysis. More recently, progress has been made in the "concerted paired electrolysis" via the combination of electrolysis and nickel catalysis.…”

Redox-Neutral Cross-Coupling Amination with Weak N-Nucleophiles: Arylation of Anilines, Sulfonamides, Sulfoximines, Carbamates, and Imines via Nickelaelectrocatalysis

“…In particular, paired electrolysis represents an attractive platform wherein the half-reactions at both the anode and cathode are simultaneously used to generate the desired intermediates or products. 44 − 47 Importantly, the combination of electrolysis and nickel catalysis led to considerable advances in C–C and C–heteroatom bond formations under mild conditions. 48 − 58 In this context, the Baran group developed a nickelaelectrocatalyzed amination reaction of aryl halides and triflates with aliphatic amines 48 and extended the scope to amino acid esters, nucleosides, and oligopeptides afterward.…”