While the majority of reported paired electrochemical reactions involve carefully matched cathodic and anodic reactions, the precise matching of half reactions in an electrolysis cell is not generally necessary. During a constant 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 a reagent in remote, Pd‐catalyzed hydrogenation and hydrogenolysis reactions. To this end, an alcohol oxidation, an oxidative condensation, intramolecular anodic olefin coupling reactions, an amide oxidation, and a mediated oxidation were all shown to be compatible with the generation and use of hydrogen gas at the cathode. This pairing of an electrolysis reaction with the production of a chemical reagent or substrate has the potential to greatly expand the use of more energy efficient paired electrochemical reactions.

Paired electrochemical reactions allow the optimization of both atom and energy economy of oxidation and reduction reactions. While many paired electrochemical reactions take advantage of perfectly matched reactions at the anode and cathode, this matching of substrates is not necessary. In constant current electrolysis, the potential at both electrodes adjusts to the substrates in solution. In principle, any oxidation reaction can be paired with any reduction reaction. Various oxidation reactions conducted on the anodic side of the electrolysis were paired with the generation and use of hydrogen gas at the cathode, showing the generality of the anodic process in a paired electrolysis and how the auxiliary reaction required for the oxidation could be used to generate a substrate for a non-electrolysis reaction. This is combined with variations on the cathodic side of the electrolysis to complete the picture and illustrate how oxidation and reduction reactions can be combined.

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...

Highly efficient synthesis of optically enriched pyrrolobenzo-1,4-diazines bearing quaternary stereocenters has been realized through the chiral Brønsted acid-catalyzed Pictet-Spengler reaction of 2-(1H-pyrrol-1-yl)anilines and α-ketoamides in good to excellent yields and enantioselectivities. Computational studies suggest an unprecedented phenomenon whereby the chiral phosphoric acid catalyst employs attractive arene C-H⋅⋅⋅N hydrogen bonding to activate the substrate and induce chirality through a triple hydrogen-bonding interaction.

We compared five methods for the determination of total and direct bilirubins in serum samples from normal controls, subjects with Gilbert's syndrome, and serum pools containing about 50 and 150 mg of total bilirubin per liter. The Kodak Ektachem method and a diazotized sulfanilic acid method with 0.15 mmol/L sodium nitrite concentrations are the only methods that gave accurate direct bilirubin values, as judged by liquid-chromatographic results. The aca method that involved p-nitrobenzene diazonium tetrafluoroborate and another diazotized sulfanilic acid method with a higher concentration of sodium nitrite (0.8 mmol/L) yielded falsely high values for direct bilirubin, which could lead to clinical confusion. The more recently introduced diazotized sulfanilic acid method of the aca gave substantially better results than the p-nitrobenzene diazonium tetrafluoroborate method but was still inaccurate. Systematic investigation of these procedures revealed that the overestimation of direct bilirubin by the diazotized sulfanilic acid method was related to the amount of unconjugated bilirubin present and its ability to react as direct bilirubin in the presence of higher concentrations of sodium nitrite. Inherent properties of p-nitrobenzene diazonium tetrafluoroborate appeared to be responsible for inaccuracies in that method, which could not be corrected by varying reagent concentration or the reaction conditions.