Recent Advances in C−H Functionalization with Electrochemistry and Various Iodine‐Containing Reagents

Abstract

Iodine‐catalyzed C−H functionalization has emerged as an attractive tool for the construction of various C−X (X=C, N, O, S, etc.) bonds, without the use of toxic transition‐metal catalysts. Nevertheless, strong chemical oxidants are usually required for the regeneration of iodine‐containing catalysts, which leads to poor atom economy and undesirable side reactions. Organic electrochemistry provides new opportunities for the assembly of various chemical bonds in an environmentally friendly manner. This Minireview discusses the recent advances of synthetic electrochemistry in C−H functionalization with various iodine‐containing reagents.

Electrochemical Generation and Use in Organic Synthesis of C‐, O‐, and N‐Centered Radicals

“…The indirect anodic oxidation at the alpha position of carbonyl compounds like methyl ketones ( 3 ), using the halide‐halogen redox mediator (I − /I 2 ), has been widely studied [13] . This reaction is an excellent option to access α carbonyl C ‐centered radicals like phenacyl‐type radicals ( 4 ), which in the presence of the halogen radical lead to α halogenated ketones ( 5 ) (Scheme 1a).…”

“…This fact, associated with the poor redox potential control of the compounds used to promote SET, [8] makes organic electrosynthesis an attractive method to prepare radicals in organic synthesis (Figure 1). [9–16] The generalities and practical aspects of organic electrosynthesis can be found elsewhere in recent publications, [17–20] where practical aspects of the electrosynthesis are reviewed.…”

Annulation Reaction of Quinoxalin-2(1H)-ones Initiated by Electrochemical Decarboxylation of N-Arylglycines

“…By using traceless electrons from the anode or cathode as redox reagents, electrochemical synthesis is regarded as an environmentally friendly and atom-economical synthetic strategy, which has drawn significant attention in the past decade. , In recent years, a large number of electrochemical methods for the construction of C–C, C–S, C–N, and C–O bonds have been disclosed. Inspired by Yu and Chen’s work, we have recently been interested in the electrochemical annulation reaction of quinoxalinones with N -arylglycines.…”

Tunable Electrosynthesis of Anthranilic Acid Derivatives via a C–C Bond Cleavage of Isatins

“…Electrochemical synthesis is recognized as a sustainable and elegant technique with electrons as the reaction reagents. , It provides a green alternative approach for C–C bond cleavage/functionalization. − For instance, in 2017, Zeng reported the acylation of electron-deficient N -heteroarenes via the scission of α-keto acids under electrochemical conditions (Scheme a) . In 2019, Huang achieved the N -formylation of indole via an electrochemical decarboxylation of glyoxylic acid (Scheme b) .…”