A review of asymmetric synthetic organic electrochemistry and electrocatalysis: concepts, applications, recent developments and future directions

The direct exploitation of ‘electrons’ as reagents in synthetic organic transformations is on the verge of a renaissance by virtue of its greenness, sustainability, atom economy, step economy and inherent safety. Achieving stereocontrol in such organic electrochemical reactions remains a major synthetic challenge and hence demands great expertise. This review provides a comprehensive discussion of the details of stereoselective organic electrochemical reactions along with the synthetic accomplishments achieved with these methods.

Electrochemically Induced Diels-Alder Reaction: An Overview

One of the most important name reactions in organic chemistry, is the Diels-Alder cycloaddition reaction. It is a chemical reaction between a conjugated diene and a substituted alkene, commonly termed the dienophile to construct a substituted cyclohexene derivative. It is the stereotypical example of a pericyclic reaction with a concerted mechanism. In synthesis, the use of electricity instead of stoichiometric amounts of oxidant or reducing agents is definitely appealing for economic, ecological and selective, reasons. In this review, we try to underscore the combination of the electrosynthesis with Diels-Alder cycloaddition reaction to establish of a powerful synthetic tool which may encourage synthetic organic chemists to use it in the future.

In Situ FTIR Spectroscopic Monitoring of Electrochemically Controlled Organic Reactions in a Recycle Reactor

An electrochemical cell coupled with a recycle loop through a transmission FTIR cell is employed in studies of two free radical organic reactions, the oxidation of allylic alcohols and the trifluoromethylation of heteroarenes. Rapid mixing through the recycle loop allows continuous monitoring of reaction progress. Electrochemical generation of free radicals allows their controlled mediation into the reaction mixture for more efficient reaction. Kinetic profiles provide mechanistic insight into reactions under electrochemical control.

Electrolytic reduction: modification of proteins occurring in isoelectric focusing electrophoresis and in electrolytic reactions in the presence of high salts

Artifacts in two-dimensional electrophoresis (2-DE) caused by the presence of salts in isoelectric focusing (IEF) have been previously described as a result of increasing conductivity and inducing electroosmosis. However, electrolysis induced by the presence of salts should not be disregarded. In this study, electrolytic reduction−oxidation reaction (redox) was found to be enhanced in the presence of salts in IEF. The consequence of the electrolytic redox leads to acidification of the low-pH region and alkalization of the high-pH region within the immobilized pH gradient (IPG) strip. As a result, a breakdown of immobilized pH buffer near the high pH region of IPG strips along with reduction of basic proteins resulted in uncharacterized artifacts in 2-DE. Electrolytic reduction in the presence of alkali and alkaline metal ions was demonstrated to reduce 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), protein disulfide bonds, and protein carboxylic acids. Importantly, semipreparative electrolytic reduction of proteins can be carried out in the presence of sodium ions in a homemade electrolytic apparatus. These findings give additional explanations to the observed artifacts in 2-DE and reveal the unknown effects of salts in IEF. Moreover, we have provided a method with the potential to convert proteins or peptides to corresponding modified products containing aldehyde groups that can be used for conjugation with amine-containing compounds.