Research articles

Step-economic access to the biologically relevant 2-hydroxybiaryl motif represents a long-standing challenge in synthetic organic chemistry. Now, a bismuth-mediated oxidative arylation of phenols and naphthols with boronic acids has been developed — supported by experimental mechanistic insight — giving a direct and practical route to this valuable molecular architecture.

The deposition of noble metals onto two-dimensional transition metal dichalcogenides is crucial for practical applications, including in catalysis and sensing, yet this process has remained difficult to control. Now, gold and silver have been shown to grow on colloidal transition metal dichalcogenide nanosheets into either atomically thin layers or nanoparticles whose sizes and morphologies depend on the relative strengths of the interfacial noble metal–chalcogen bonds.

Although biaryl rings can be easily formed via cross coupling, their tetrahedral, high-fraction sp³ equivalents cannot. Now the scope, mechanism and biological profile of a general attached-ring synthesis has been probed. This provides direct access to full bridgehead substitution via sp³–sp³ coupling and enables rapid entry to natural product space.

The anti-Markovnikov hydroarylation of unactivated alkenes with unactivated arenes has been achieved with high selectivity by using nickel catalysts bearing large N-heterocyclic carbene ligands. Energy decomposition analysis indicates that the high activity of the catalysts with large carbene ligands arises from stabilizing non-covalent interactions rather than steric effects.

Porous liquids promise to combine the advantages of the porosity of solids with those of the fluidity of liquids. Now, a permanently porous ionic-liquid coordination cage has been assembled that encapsulates isomers of butanol and propanol with some size and shape selectivity, as well as three gaseous chlorofluorocarbons with a size-dependent affinity.

Although methods exist for the construction of CF₃-containing stereocentres, the utilization of α-trifluoromethyl carbanions remains challenging because of the propensity for fluoride elimination. A strategy has now been developed to stabilize these carbanions through a neighbouring cationic Pd complex and the corresponding Pd-stabilized zwitterions participate in asymmetric cycloadditions with a broad range of acceptors.

Does aromaticity have a size limit? Evidence is presented for global aromaticity in porphyrin nanorings with circuits of up to 162 π-electrons. The conformation of the nanoring can be altered by changing the template, which in turn controls the aromaticity. Whenever a ring current is observed, its direction is correctly predicted by Hückel’s rule.

Homogeneous photocatalysts for the conversion and storage of solar energy typically feature separate sensitizer–catalyst assemblies, whereas previous examples of single-chromophore single-molecule photocatalysts are inefficient and do not use significant portions of the visible spectrum. Now a dirhodium single-chromophore single-molecule catalyst has been developed that generates hydrogen using low-energy light through a previously unobserved mechanism.

The Varkud satellite ribozyme, which catalyses site-specific RNA cleavage and ligation, is an important model to understand RNA catalysis. Now, a combination of theoretical and experimental work has revealed new details about its catalytic mechanism. Mg²⁺ is shown to play an important role in organizing the active site, and the proton transfers in the transition state have also been identified.

Homooligomerization systems can be used to construct nanoarchitectures and to aid understanding of natural analogues. But the formation of such artificial systems with structural diversity and complexity comparable to that of biological systems is challenging. Now, an artificial branched kissing-loop motif has been designed, which links tiles folded from a single strand of RNA to give diverse homooligomeric nanostructures.

A conjugated diradicaloid cage has been synthesized and its aromaticity was investigated. The neutral compound and the dication have dominant monocyclic conjugation pathways and both are aromatic (the former following Hückel’s rule and the latter Baird’s rule). The tetracation ([6n + 4] π-electrons) exhibits global 3D antiaromaticity whereas the hexacation ([6n + 2] π-electrons) exhibits global 3D aromaticity and has high D₃ symmetry.

Meroterpenoids are mixed terpenoid–polyketide natural products that exhibit a range of biological activities. A hybrid synthetic strategy that combines biocatalytic and radical-based methods has now been developed and it enables eight different oxidized meroterpenoids to be made in just 7–12 steps from commercially available materials.

Carbon capture technologies are poised to play an important role in reducing CO₂ emissions to mitigate global warming, but their cost prevents their extensive use. Now, CO₂ capture and utilization have been combined using a triple-level dynamic combinatorial approach. CO₂ was spontaneously captured by industrial polyamines to create libraries of ligands that can be used for the separation and recovery of metals.

The mechanochemical activation of [4]-ladderane/ene has been studied and found to exhibit cascade unzipping and a consistent stereochemical distribution of products under various conditions and in different polymer backbones. Ab initio steered molecular dynamics simulations revealed unique non-equilibrium dynamic effects in the mechanochemistry of ladderane, cascade activation and reaction pathway bifurcation.