Organocatalyzed Anodic Oxidation of Aldehydes

Abstract

A method for the catalytic formation of electroauxiliaries and subsequent anodic oxidation has been developed. The process interfaces N-heterocyclic carbene-based organocatalysis with electro-organic synthesis to achieve direct oxidation of catalytically generated electroactive intermediates. We demonstrate the applicability of this method as a one-pot conversion of aldehydes to esters for a broad range of aldehyde and alcohol substrates. Furthermore, the anodic oxidation reactions are very clean, producing only H(2) gas as a result of cathodic reduction.

Synthetic Organic Electrochemical Methods Since 2000: On the Verge of a Renaissance

“…Boydston devised an electrochemical method to convert aldehydes into esters through N -heterocyclic carbene (NHC) catalysis (Figure 15A). 246 Under this system, a Breslow intermediate formed between the aldehyde and NHC is oxidized under a low potential (+0.1 V vs Ag/AgNO 3 ) whereupon interception of the oxidized product by an alcohol leads to the ester product. The reaction may be conducted using various types of batteries as the power source.…”

Organic reactions for the electrochemical and photochemical production of chemical fuels from CO2 – The reduction chemistry of carboxylic acids and derivatives as bent CO2 surrogates

“…Although outside of the scope of the current discussion as it relates to an oxidative process, we would like to note an example of electrode-driven organocatalytic process [37]. Bodyston and coworkers report the preactivation of an aldehyde via a NHC organic fragment.…”

Recent Developments in Organocatalyzed Electroorganic Chemistry

“…27 Although direct bulk electrolysis of Breslow intermediates were previously unknown, cyclic voltammetry studies of Breslow intermediates derived from thiazolium precatalysts showed that these intermediates have much lower oxidation potentials than their parent aldehydes (¹0.9 and >2 V vs. SCE, respectively).…”