Chemoselective Electrochemical Oxidation of Secondary Alcohols Using a Recyclable Chloride-Based Mediator

Abstract

Selective anodic oxidation of alcohols in the presence of other functional groups can be accomplished using nitroxyl radical mediators. However, the electrochemical chemoselective oxidation of secondary alcohols in the presence of primary alcohols is an unsolved issue. Herein, we report an electrochemical procedure for the selective oxidation of secondary alcohols using an inexpensive chloride salt that acts as redox mediator and supporting electrolyte. The method is based on the controlled anodic generation of active chlorine species, which selectively oxidize secondary alcohols to the corresponding ketones when primary hydroxyl groups are present. The method has been demonstrated for a variety of substrates. The corresponding ketones were obtained in good to excellent yields. Moreover, the chloride salt can be easily recovered and reutilized by a simple extraction procedure, rendering the method highly sustainable

Electrochemical Oxidation of Alcohols Using Halogen Mediators

“…In 2022, the oxidation of alcohols 30 including diols having both secondary and primary hydroxy moieties was demonstrated by the group of Cantillo (Scheme 12). [28] The reaction of diols was performed with Me 4 NCl in the presence of acetic acid under constant current conditions, providing the corresponding hydroxy ketones 31 in good to high yields via the selective oxidation of a secondary hydroxy group. Simple primary and secondary alcohols were also transformed to the corresponding products under the reported reaction conditions.…”

Development of an open-source flow-through cyclic voltammetry cell for real-time inline reaction analytics

“…Electrochemical methods can realize alcohol oxidations without the need for an external oxidant. Redox mediators are commonly used, including halides, 20 TEMPO, 21 or NiOOH species. 22 Recently, Lei and co-workers have reported a mediator-free electrochemical method for the oxidation of alcohols using graphite electrodes.…”