Electrifying Sustainability on Transition Metal‐Free Modes: An Eco‐Friendly Approach for the Formation of C−N Bonds

Abstract

Embracing sustainable green methodologies and techniques in chemical transformations has always been in the limelight to the synthetic community. Electrosynthesis has emerged as a powerful, sustainable synthetic tool for molecular synthesis exploiting inexpensive electricity in place of sacrificial chemical oxidizing/reducing reagents. Herein, recent advances in the incorporation of transition metal‐free redox mediators in electrosynthesis for the construction of C−N bonds are outlined. Furthermore, conjugation of this strategy with flow catalysis allows easy scale up of the synthesis of molecular assembly. This comprehensive Review provides an overview of metal‐free mediated electro‐construction of C−N bonds, focusing on the reaction mechanisms involved and its synthetic applications.

Recent Progress in Electrocatalytic Urea Synthesis under Ambient Conditions

“…How to resolve these challenges is crucial to promote the rapid development of this rising research field. Though there have been several reviews introducing the synthesis of C–N bond formation by electrosynthesis, ,,− experimental and theoretical research progress has not been specially and critically reviewed toward urea electrosynthesis. In this perspective, we first discuss the experimental measurement sets, identification, and quantification of urea and other parallel products.…”

Electrochemical [4 + 1] Tandem sp3(C–H) Double Amination for the Direct Synthesis of 3-Acyl-Functionalized Imidazo[1,5-a]pyridines

“…Halogen ions, one of the most versatile and cost-efficient mediators, are always combined with irreversible halogenation in indirect electrosynthesis and can enhance the reaction efficiency and functional group compatibility . Apparently, the indirect electrocatalytic functionalization of sp 3 hydrocarbons with a redox mediator as a green synthetic strategy improves the synthesis efficiency and shortens the synthesis steps via employing nonfunctionalized cheap starting materials . In virtue of the formal achievements and the advantage of indirect electrosynthesis, herein, we report a chemoselective electrochemical tandem [4 + 1] sp 3 hydrocarbon double amination for the direct synthesis of 3-acyl imidazo­[1,5- a ]­pyridines from pyridine ethylamines and acetophenones.…”

Electrochemical TEMPO-Catalyzed Oxidative Ugi-Type Reaction

“…In this specific context, we recently began to study the synergistic merger of electrosynthesis with IMCRs. Performing an anodic oxidation, direct or indirect, is particularly appealing as it avoids the use of stoichiometric oxidants by employing perfectly sustainable reagents: electrons and protons. − Moreover, such oxidation methods are typically very mild, giving better chances to reach better chemoselectivity. After establishing the proof of concept via the development of an electrochemical oxidative Ugi–Joullié reaction, we now report the first alcohol-based oxidative Ugi reaction, thanks to an indirect anodic oxidation process (Scheme , eq (c)).…”