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Paired electrolysis converts industrial SO₂ directly into valuable cyclic sulfite esters, turning a common pollutant into useful chemicals. Mechanistic studies reveal key intermediates, offering a sustainable and versatile platform for green organosulfur synthesis and pollutant valorization.

Phenolic compounds have long captivated the interest of organic synthesis, particularly in their quest for selective hydroxylation of arenes using H₂O as a hydroxyl source but the inherent high reactivity and low redox potential of phenols often lead to undesirable overoxidation byproducts. Here the authors develop an electrophotochemical approach, finetuning substrate oxidative potential and enabling para-selective hydroxylation of anilides.

C(sp³)–H fluoroalkylation of bioactive molecules is a challenge. Now, a scalable and site-selective allylic fluoroalkylation of terpenes and olefins has been developed using a cobaloxime catalyst. Mechanistic studies reveal the process probably proceeds through halogen-atom transfer and hydrogen-atom transfer steps.

The dehydrogenative C-H/N-H cross-coupling serves to install nitrogen functionalities into arenes with the highest atom economy. Here, the authors report an electrochemical cross-coupling between aromatics and sulfonimides through an N-radical addition pathway under oxidant- and catalyst-free conditions.

The difunctionalization of diazo compounds, traditionally with one nucleophile and one electrophile, is a powerful strategy. Here, the authors develop a path of electrochemical oxidative difunctionalization of diazo compounds with two different nucleophiles.

Organocopper species are widely used in synthetic chemistry. Here the authors study the structure of the anionic complex formed from copper salts and lithium halides, showing it to be a key intermediate in the formation of organocuprates, and also show that Cu(II) precursors can form Gilman reagents.

Cross coupling via the activation of two carbon-hydrogen bonds avoids the need for organometallic coupling partners and associated waste. Here, the authors report a radical process that allows selective coupling between alkynes and non-activated C(sp³)-H groups via a multimetallic catalytic system.

Functionalization of unactivated C–H bonds is an attractive strategy to introduce functionality without the need for pre-functionalized starting materials. Here the authors combine cobalt catalysis with photoredox catalysis, allowing arene-azole cross-coupling under oxidant-free conditions.

1,2-Aminoxygenation of alkenes without extra oxidant is a practical yet challenging way to prepare β-amino alcohols. Here, the authors report an electro-oxidative route achieving such a goal with H2 evolution, exhibiting broad scope and application potential.

Allylic amination of unactivated alkenes with aliphatic amines is a long-standing synthetic challenge in organic chemistry. This is now accomplished in an oxidant-free, site-selective process by using a combination of a photocatalyst and cobalt complex for the coupling of olefins and alkyl amines with hydrogen evolution.

Electrochemical oxidative C–C bond cleavage and functionalization are rarely developed due to the inertness and weak electronic bias of C–C bonds. In this study, the authors report the electrochemical C–C bond cleavage and 1,3-difluorination, 1,3-oxyfluorination and 1,3-dioxygenation of arylcyclopropanes under catalyst-free and external-oxidant-free conditions.

Alcohols are very useful building blocks in organic synthesis, however C–H functionaliztion in presence of free –OH groups is highly challenging. Here, the authors report a selective visible light-promoted α-functionalization of free alcohols with heteroarenes mediated by Selectofluor.

Oxidative carbonylation using CO/O₂ is an attractive strategy to construct carbonyl compounds, but the explosive limit of the gas mixture hampers its application. Now, this safety issue is overcome in the aminocarbonylation of alkynes by replacing the external oxidant O₂ by electrochemistry facilitating a mild and safe reaction.

Oxidative C–H/N–H cross-coupling is a convenient method to construct C–N bonds, however this is rarely achieved in a sustainable manner. Here, the authors show an oxidant-free electrochemical C–H/N–H cross-coupling between electron-rich arenes and diarylamines to afford triarylamines with exclusive para-selectivity.

Alcohol oxidation to carbonyl compounds is a very useful functional group transformation in organic synthesis. Here, the authors perform the direct electrochemical oxidation of various alcohols to the corresponding ketones in a continuous-flow reactor without external oxidants, base or mediators.

A sequence of a Diels–Alder reaction and oxidation is a powerful route to valuable aromatic compounds. Here, the authors report a more atom-economical oxidant-free strategy involving a Diels–Alder with H₂ evolution under noble-metal-free photoredox conditions.

Electrochemical oxidation provides a green alternative to the use of hazardous chemical oxidants and forcing conditions. Here, the authors show the electrocatalytic cross-coupling of phenols and indoles to generate biologically relevant benzofuroindolines in high yields.

Catalytic methodologies that incorporate commodity chemicals ethylene and ethyne into fine chemicals are quite limited. Here, the authors show a cobalt-catalyzed electrochemical C-H/N–H [4+2] annulation of aryl/vinyl amides with ethylene or ethyne to produce N-heterocycles in absence of oxidants.

Methods for deuterium labelling of C–H bonds under mild conditions are sought after. Now an electrocatalytic method for H/D exchange via a radical-mediated pathway is described, using a boron cluster as a radical shuttle during the coupling process of deuterium and carbon radicals.

Anodic C(sp³)–H bond oxidative functionalization that involve C(sp³)–M, a C(sp³) radical or a C(sp³) cation intermediate with hydrogen evolution can be achieved by direct and indirect electrolysis. This Review discusses both strategies, and gives examples of the electrochemical methods developed for such functionalization reactions.

A heterogeneous nickel-catalysed deuteration reaction of benzylic C(sp³)–H bonds in alkylarenes and methylarenes using D₂O is developed. Such metal–H₂–D₂O systems could be extended to other catalytic reactions for the preparation of deuterium-labelled compounds in the future.

Transition metal-catalyzed regioselective difunctionalizations of alkenes with two different functional groups are useful for preparing organic compounds, but the construction of two new C–C bonds is challenging. Here, the authors report cobalt-catalyzed regioselective difluoroalkylarylation of alkenes with solid arylzinc pivalates and difluoroalkyl bromides, through a cascade Csp³ ‒Csp³/Csp³ ‒Csp² bond formation.

Biomass valorization is a way to promote the ‘waste-to-wealth’ concept, which is a prerequisite condition for a future sustainable lifestyle. Here, the authors demonstrate a methodology to prepare chitin-derived supramolecular nanowires-stabilized single-atom site platinum catalysts.

Ligands and additives are often utilized to stabilize low-valent catalytic metal species experimentally, while their role in suppressing metal deposition has been less studied. Here, the authors report an on-cycle mechanism for CoCl2bpy2 catalyzed Negishi-type cross-coupling describing a full catalytic cycle for this reaction using multiple spectroscopic studies.

Polycystic kidney disease 2-like 1 protein (PKD2L1) is a voltage-dependent calcium-dependent nonselective ion channel involved in sour taste perception and regulation of pH-dependent action potential of spinal cord neurons. Here the authors present the 3.4 Å cryo-EM structure of PKD2L1 in the open state and propose a model for the gating mechanism.

Reductive deuteration and deuterodefluorination of arenes and heteroarenes is achieved through a scalable and general electrocatalytic method using a nitrogen-doped ruthenium electrode and heavy water.

Simultaneous functionalization of reactive and inert remote sites presents a powerful approach to access complex molecules, yet it is hindered by precise remote C(sp³)–H activation. Now, the accurate translocation of functional groups and remote C–H desaturation has been achieved in parallel through combining functional group migration and cobalt-promoted hydrogen atom transfer.

Direct radical C–H amination strategies have exhibited innovation, but challenges remain with C–H amination of electron-poor nitroarenes due to the essence of the electron-deficient nitrogen radical. Herein, the authors report a transition metal-free dehydrogenative C(sp²)-H/N-H cross-coupling between electron-poor nitroarenes and amines.

While electrosynthesis represents a green and advantageous alternative to traditional synthetic methods, electrochemical reactions still suffer from some drawbacks that require further efforts in order to fully express the potential of electricity-driven transformations. In this Comment, we will briefly discuss both the advantages and limitations of electrosynthesis, especially when compared with the other traditional synthetic organic methods, and share some forward-looking thoughts on the future developments of electrochemical reactions.

A method for the selective deuteration of anilines, indoles, phenols and heterocyclic compounds, including natural products and other bioactive molecules, has been developed. The nanostructured iron catalyst that underpins this process is prepared by combining cellulose with iron salts and has been used for the preparation of deuterated compounds on up to a kilogram scale.

Metalloporphyrin compounds are studied as models of cytochrome P450, which is capable of catalysing oxidative reactions. Here, reaction conditions are varied to allow spectroscopic observation of oxidant-metalloporphyrin adducts and metal-oxo intermediates, which may elucidate reaction mechanisms.

Preventing metal deposition by cathodic reduction under direct current electrolysis conditions is a formidable challenge in transition-metal-catalysed electrosynthesis. Now, an asymmetric-waveform alternating current (a.c.) electrolysis approach is developed for silver-catalysed C–H phosphorylation where this a.c.-based approach regenerates the silver catalyst and keeps the catalyst loading balanced during the reaction.

Electron transfer processes are almost ubiquitous, yet hard to understand thoroughly due to the variability of catalytic species involved. Now, a detailed mechanistic picture of the electron transfer associated with polypyridine nickel systems has been reported, offering an answer to the electron transfer puzzle of these complexes.

Enriching the chemical space of polycyclic heterocycles is of high value in chemical biology. Here, the authors report an electrooxidative protocol for the regioselective dearomative annulation of indoles and benzofurans under undivided cell conditions and obtain five- to eight-membered fused heterocycles.

Photochemical and electrochemical approaches to protein and peptide modification offer a valuable complement to the use of stoichiometric reagents. Here recent developments in bioconjugation methodology relying on single electron transfer are described.