Research articles

The selective functionalization of strong, neutral C(sp³)–H bonds, such as in alkanes, is synthetically challenging. Now, a transition-metal- and photosensitizer-free strategy employing allyl bromides as reagents and sodium fluoride as an activator has been developed for the selective C(sp³)–H functionalization of alkanes, cycloalkanes and other relatively unreactive molecules.

Controlling the number and arrangement of ligands around metalloclusters is challenging. Now, a method for imparting site-differentiation to homoleptic clusters is reported in which the site-differentiation pattern is dictated by the steric profile of the incoming ligand.

Controlling the self-assembly of large coordination cages is challenging owing to entropic costs and difficulties in error correction. Now an array of large cages prepared by the rational design of alterations that allow for the tuning of the dihedral angle between pentagonal subunits is reported.

1,3-Disubstituted bicyclo[1.1.1]pentanes are linear bioisosteres for para-substituted benzene rings; however, the lack of practical reagents for the introduction of bicyclopentane currently impedes their application, especially in drug development. Now, stable thianthrenium-based bicyclopentane reagents are reported and their use in O-, N- and C-alkylation reactions demonstrated.

The heavy analogues of ynolates or ketenyl anions have not yet been studied. Here the synthesis, isolation and characterization of a sila-ketenyl anion, the silicon analogue of a ketenyl anion, are reported through the reaction of silyl-radical anions with CO.

A lack of guiding principles limits the preparation of two-dimensional (2D) materials prepared by a solution-phase growth route. Now, a general qualitative model for 2D material growth is proposed and applied to fabricate more than 30 nanomaterials, allowing 2D growth to be controlled by only tuning the reaction concentration or temperature.

Photoinduced catalytic systems typically consist of a transition metal catalyst and a photoredox catalyst. Now spiro-fluorene-indenoindenyl-Rh(I) complexes are reported as a single catalytic system that extends the scope of C–H borylation of arenes and [2+2+2] cycloaddition of alkynes to challenging substrates under irradiation with blue light.

Carbon- and silicon-based triplet diradicals with two unpaired electrons are proposed as intermediates in organic and organometallic reactions but their isolation is challenging. Now, isolable 1,3-disilapyrroles are reported to act as organosilicon-based delocalized triplet diradicals and mediate the cleavage of the CO triple bond and C(sp³)–H bond activation.

Hydrogen peroxide is an important industrial feedstock but its synthesis is energy intensive. Now, a highly efficient Ga-N₅ atomic site is reported with a high solar-to-chemical conversion efficiency for direct photocatalysis of water into hydrogen peroxide.

Controlled radical polymerization of fluorinated monomers typically synthesizes fluoropolymers of limited molecular weights with poor control. Now the controlled copolymerization of various fluoroalkenes under ambient conditions is reported by combining a redox-relay pathway and thermally activated delayed fluorescence catalysis.

The amination of C–H bonds is a sustainable approach to prepare important nitrogen-containing molecules; however, regio- and stereoselectivity is difficult to control. Now the synthesis of α-monosubstituted and α,α-disubstituted α-amino acids from abundant carboxylic acids has been achieved through Fe-catalysed asymmetric intermolecular C(sp³)–H amination by directed stereocontrolled nitrene insertion.

Complex molecule synthesis involves speculative retrosynthetic planning and resource-intensive experimental evaluation. Now, a complementary strategy is reported that combines human-generated synthetic plans with computational prediction to accelerate this process. A machine learning model was trained to predict the yield of radical cyclization and guide the syntheses of clovane sesquiterpenoids.

BODIPYs possessing boron-stereogenic centres are rare and it is challenging to develop catalytic methodologies to enantioselectively prepare these molecules. Now, a palladium-catalysed desymmetric intramolecular C–H arylation reaction for the enantioselective synthesis of boron-stereogenic BODIPYs is reported, which gives access to various six- to nine-membered chiral boron heterocycles with good enantioselectivity.

Preparing enantioenriched aliphatic amines from readily available feedstocks is challenging to achieve. Now, direct enantioconvergent amination of racemic secondary alcohols using a variety of aliphatic primary amines is reported, catalysed by chiral iridium and phosphoric acid species. This atom-economical strategy streamlines the enantioselective synthesis of N-containing commercial drugs and analogues.

The direct electrosynthesis of acetic acid from CO₂ typically has the drawback of CO₂ crossover. Now, a cascade approach for the electroreduction of CO₂ to CO, followed by CO to acetic acid, is reported in which off-target intermediates are destabilized, leading to an acetic acid Faradaic efficiency of 70%.

Well-defined single-atom alloy (SAA) nanocrystals possess isolated atom centres and tunable electronic properties but are challenging to synthesize. Here, a direct solution-phase synthesis of Cu/CuAu core/shell nanocubes with tunable SAA layers is reported. The Cu/CuAu nanomaterial is highly active for the electrocatalytic conversion of nitrate into ammonia.

Functional-group transfer strategies using surrogates to avoid handling hazardous reagents are often limited to monofunctionalization reactions. Now, an operationally simple and mechanistically distinct photocatalytic transfer strategy for vicinal dihalogenation of carbon–carbon multiple bonds, such as in alkenes, alkynes and allenes, using readily synthesized oxime-based dihalogen surrogates is reported.

Trial-and-error synthesis and labour-intensive characterization procedures hinder the development of nanocrystals. Now, a data-driven robotic synthesis approach is used to prepare gold and double-perovskite nanocrystals. This approach combines data mining of synthesis parameters, robot-assisted synthesis and characterization, and machine-learning-facilitated inverse design of the nanocrystals.

Copper-catalysed enantioconvergent radical Michaelis–Becker-type C(sp³)–P cross-coupling of diverse racemic alkyl halides with H-phosphonates has been achieved, overcoming the competing S_N2 mechanism. Multidentate chiral ligands are crucial to prevent catalyst poisoning and enhance the reducing capability of the copper catalyst for initiation of the radical process.

Alkynes are key building blocks in synthetic chemistry and materials science. Now, a modular synthesis of alkynes, through coupling of carboxylic acid esters with gem-diborylalkanes, is reported. Using isotopically labelled substrates, products with a ¹³C label at either or both carbons of the alkyne unit can be produced.