Aryl radicals are important and versatile active intermediates in synthetic chemistry, and the chemical conversions involved are regarded as perfect complements to the transition-metal-catalyzed arylation reactions. The formation of aryl radicals is mainly achieved through reductive systems. Electrocatalysis has a safe and controllable potential range that can easily attain a reduction potential beyond the range of chemical reductants and excited photocatalysts, offering a synthetically attractive and environmentally friendly alternative for the production of aryl radicals. Remarkable achievements in the electrochemical functionalization of aryl radicals have been reported. This review primarily focuses on the generation of aryl radicals via an electroreduction strategy, and systematically elaborates on synthetic applications, scope, and limitations of the substrates. The full spectrum of aryl radical precursors applied in the electroreduction strategy, including aryl halides, aryl diazonium salts, arylazo sulfones, aryl amines, nitroarenes, aryl quaternary ammonium salts, aryl triflates, and aryl thianthrenium salts, is reviewed.

The direct air-oxidation strategy enables the transformation of arylphosphine oxides into phosphinoyl radicals, which are subsequently used in the synthesis of benzo[b]phosphole oxides by combining with various alkynes.

An unprecedented and sustainable electrochemically driven oxidative 5- exo-dig radical cyclization of N -propargylbenzamides with alcohols for the synthesis of structurally diverse oxazole ketals is described.

A new and convenient protocol is presented here for the synthesis of 3,6,8-tribromoquinolines via cascade cyclization of N-(3-phenylprop-2-ynyl)anilines employing N-bromosuccinimide as an electrophile. The metal-free process is carried out under mild conditions and is compatible with a variety of substituents. The Sonogashira coupling reaction regioselectively occurs at position C-6 of the obtained products.

An efficient and practical bromination/dehydrogenation of tetrahydroquinolines was developed for the one-pot construction of polybromoquinolines under mild conditions. NBS not only acts as an electrophile, but also as an oxidant in this reaction.

The first total synthesis of 5′-O-α-d-glucopyranosyl tubercidin was successfully developed. It is a structurally unique disaccharide 7-deazapurine nucleoside exhibiting fungicidal activity, and was isolated from blue-green algae. The total synthesis was accomplished in eight steps with 27% overall yield from commercially available 1-O-acetyl-2,3,5-tri-O-benzoyl-β-d-ribose. The key step involves stereoselective α-O-glycosylation of the corresponding 7-bromo-6-chloro-2′,3′-O-isopropylidene-β-d-tubercidin with 2,3,4,6-tetra-O-benzyl-glucopyranosyl trichloroacetimidate. All spectra are in accordance with the reported data for natural 5′-O-α-d-glucopyranosyl tubercidin. Meanwhile, 5′-O-β-d-glucopyranosyl tubercidin was also prepared using the same strategy.