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Theoretical studies predict that the introduction of nitrogen atoms onto cycloparaphenylene frameworks would add fascinating properties but few partially N-doped carbon nanorings have been synthesized. Here, the authors report the synthesis of a cycloparaazine, where every para-connected aromatic moiety consists of a N-heterocycle, and two other highly N-doped carbon nanorings.

C to N atom swapping in indoles is introduced that gives indazoles through oxidative cleavage of the indole heteroarene core and subsequent ring closure, adding another method to the field of skeletal editing.

The direct C−H-difluoromethylation of pyridines represents a highly efficient economic way to access azines. However, the direct meta-difluoromethylation of pyridines remains elusive. Here, the authors demonstrate switchable meta- as well as para-C−H difluoromethylation of pyridines through radical processes by using oxazino pyridine intermediates.

Selective remote functionalization of aliphatic C(sp³)−H bonds is highly challenging and often requires transition metals and/or directing groups. Here, the authors show the γ-arylation of aliphatic alcohols via a two-step radical translocation and subsequent radical aryl migration.

An iron-catalysed radical Markovnikov hydroamidation of alkenes using a cyanamide reagent is reported. The method achieves C–N bond formation with high yields and selectivity and is applicable to a wide range of alkenes and natural products. The cyanamide functionality can be transformed into various functional groups, highlighting its potential for advanced applications in natural product synthesis.

Direct acylation of sp3 C−H bonds in complex organic molecules is not well established compared to that of sp2 C−H bonds. Here, the authors report the combination of N-heterocyclic carbene (NHC) and photoredox catalysis for the direct and site-selective acylation of benzylic C−H bonds.

Fluorinated or fluoroalkylated allenes are versatile building blocks for medicinal and material chemistry. Here, the authors show a regioselective trifunctionalization of 1,3-enynes proceeding through double C-F bond formation and concomitant installation of a -NSO₂Ph group to the allene moiety.

Alkenes are attractive building blocks for synthetic organic chemists as they are widely available and can be functionalized in ways that enable manifold further transformations. Here, the authors present a suite of hydrofunctionalizations of alkenes that lead to regioselective delivery of azides and halogens, under mild conditions, with iron catalysis.

Skeletal editing enables diversification of compounds not possible by applying peripheral editing strategies. Now, a catalyst-free atom-pair swap strategy for pyridine editing has been developed via one-pot sequential dearomatization, cycloaddition and rearomative retrocyclization. Benzenes and naphthalenes with precisely installed functional groups are produced, and the mild conditions enable late-stage skeletal diversification of pyridine cores.

Using a photocatalytic phosphine-mediated radical process under mild conditions enables direct hydrogen atom transfer to closed-shell π systems for activation of water.

The Mizoroki–Heck reaction forms C−C bonds between aryl halides and alkenes. For electron-deficient alkenes, β-coupled products are typically formed and synthesizing α-arylated products is challenging. Now, a triple catalysis system (nickel, photoredox catalysis and sulfinate) enables regioirregular formal Mizoroki–Heck reactions for electron-deficient alkenes and styrenes to give α-arylated alkenes.

Despite the importance of unsymmetrical disulfides in various fields such as food chemistry, pharmaceutical industry, and polymer science, the nondirected intermolecular disulfuration of C-H bonds remains challenging. Here, the authors report the conversion of aliphatic C(sp³)-H bonds and aldehydic C(sp²)-H bonds into the corresponding C-SS bonds with tetrasulfides (RSSSSR) as radical disulfuration reagents.

The α-arylation of amides via aryl migration has attracted considerable interest in recent years. Here, the authors report a method for the preparation of bulky α-quaternary amides via a polar-radical crossover enolate oxidation-aryl migration cascade.

On-surface dehydrogenative bond formation between sp³-hybridized carbon atoms usually requires high temperatures. Now, it has been shown that the higher homologue, silicon, can undergo dehydrogenative polymerization at room temperature on metal surfaces. This process creates well-ordered structures on Au(111) and Cu(111), with different stereoselectivity depending on the metal.

This Review draws an analogy between acid–base catalysis and redox catalysis. The 'electron is a catalyst' paradigm unifies mechanistically an assortment of synthetic transformations that otherwise have little or no apparent relationship. Various radical cascades catalysed by the electron are discussed.