On-Demand Electrochemical Synthesis of Tetrakisacetonitrile Copper(I) Triflate and Its Application in the Aerobic Oxidation of Alcohols

Abstract

An on-demand electrochemical synthesis of copper­(I) triflate under both batch and continuous flow conditions has been developed. A major benefit of the electrochemical methodology is that the only byproduct of the reaction is hydrogen gas, which obviates the need for workup and purification, and water is not incorporated into the product. Upon completion of the electrochemical synthesis, solutions are directly transferred or dispensed into reaction mixtures for the catalytic oxidation of benzyl alcohol with no requirement for workup or purification.

Electrochemical Synthesis of Gold‐N‐Heterocyclic Carbene Complexes**

“…This suggests that the stability of the Au(I) ions in the solution leads to the contrasting reactivity when compared to Cu. Acetonitrile is a good ligand for Cu(I) but less so for Au(I) [19c,20] . As such, the Au(I) ions rely on the presence of a coordinating anion, like halides, to stabilize them in solution.…”

Development of a multistep, electrochemical flow platform for automated catalyst screening

“…38 Examples of the electrochemical synthesis of catalysts and the concurrent use in reactions in a multistep fashion remain underrepresented both in batch and under continuous reaction conditions. [39][40][41] Due to electrons being used as reagents, electrochemistry enables the production of a clean catalyst solution, that can be used in a subsequent reaction without the need for purification. Separating the electrochemical formation of the catalyst and the catalytic steps allows the use of substrates that would decompose under the electrochemical conditions.…”

“…We have previously demonstrated the continuous synthesis of Cu-NHCs and Cu(I) triflate for use in batch catalysis. 14,40 The continuous setup for the electrochemical step allows for particularly mild reaction conditions, high-throughput and good reproducibility. Wirth and co-workers used electrogenerated hypervalent iodines for the oxidation of alcohols, 39 in which the spacial separation was important, as some of the alcohols show lower oxidation potentials than the iodine precursor and would have undergone oxidation instead.…”