News & Views in 2022

The Paternò–Büchi reaction is a useful approach in organic synthesis to prepare oxetanes. Understanding the mechanism of this reaction is required for the prediction and control of the diastereoselectivity of the products.

A polymerization strategy — termed CAMMP — combines two types of olefin metathesis monomers to produce degradable copolymers without sacrificing the mechanical properties of the equivalent homopolymer.

Polyvinyl chloride (PVC) is challenging to recycle owing to the formation of hydrochloric acid during depolymerization at high temperatures. Now, a method for upcycling PVC that relies on its intrinsic reactivity in a low-intensity electrochemical process is reported, which can be exploited to chlorinate arenes.

Controllable cleavage and conversion of strong C(sp³)–H bonds remains a challenging task in organic synthesis. Here, a reaction design combining hydrogen atom transfer and copper catalysis is developed which allows enantioselective alkene difunctionalization using aliphatic C–H bond activation.

Chiral tetrahedral carbon atoms bearing functional groups amenable to functionalization offer numerous synthetic opportunities. Catalysed by copper pyridine-bis(oxazoline) complexes, the developed alkynylallylic substitution provides 3-substituted 1,4-enynes with excellent regio- and stereocontrol.

Inverse vulcanization uses high temperatures to form sulfur-rich polymers. Now, using a photoinduced method, polymerization occurs at ambient conditions enabling a broader selection of viable comonomers compared with existing routes, as well as eliminating the formation of toxic gas.

Atomically thin materials have exciting physicochemical properties but multi-element and non-layered 2D materials are difficult to prepare by conventional methods. Now, a flux-assisted method is reported, enabling the synthesis of such 2D materials by confining reaction space.

Methods for electrochemical recycling of microplastic waste to value-added products are extremely sought-after. Here, a tandem photoelectrochemical-bioelectrocatalytic approach converts microplastics to chemical fuels and uses the microplastics as an electron source for electrochemical transformations.

β-Hydride and β-heteroatom eliminations are competitive processes in many Pd-catalysed reactions but general strategies for controlling this selectivity have not been established. Now, a mechanistic study of Pd-alkyl complexes demonstrates that the choice of phosphine ligands and leaving groups controls selectivity.

Bifunctional catalysts containing metal and acid sites are used industrially in alkane hydroconversion. Now, the nanoscale spatial separation of the two active sites is shown to promote hydroisomerization and inspires design principles for this type of catalyst.

Heteroepitaxial growth of single-crystal films typically requires stringent matching of the specific lattice ordering with the underlying substrate. Now, amorphous MoTe₂ thin films are shown to transform into wafer-scale 2D single-crystals through seeded growth on the surface of any arbitrary substrate.

Dual-atom catalysts show potential for complex reactions, but their controllable preparation is challenging. A method to transform a Ni nanoparticle into a Ni₂N₆ dual-atom structure on a carbon support yields a catalyst with precisely controlled atomic site distances, giving excellent performance for CO₂ electroreduction.

Adding a promoter to a catalytic reaction can dramatically alter the performance and reactivity of a chemical transformation. By incorporating a Brønsted acid promoter to a photocatalysed reaction, previously unreactive C–H bonds can be functionalized, enabling the discovery of drug molecules.

Making chiral molecules by C–H bond activation using inexpensive, earth-abundant metal catalysts is challenging. Now, a cobalt salt combined with a salicyl-oxazoline ligand enables a C–H activation and annulation process and the introduction of axial chirality around a C–N bond.

Noble metal chalcogenides are rapidly becoming attractive materials in several areas of nanoscience; however, their synthesis remains challenging. Now, a simple cation exchange protocol has been employed to prepare these materials in various phases and morphologies.

Nature has evolved several biosynthetic CO₂ fixation pathways for the conversion of CO₂ into multi-carbon molecules. Now, a synthetic acetyl-CoA bi-cycle is reported that offers increased carbon efficiency by rewiring carbon fixation and non-oxidative glycolysis with implications for industrial gas fermentation.

Catalytic intramolecular C–H amination via nitrene transfer typically yields N-heterocycles which can be unmasked to amino alcohols and diamines. Now, an enantioselective Co-catalysed 1,5-C–H amination to form cyclic sulfamidates from alcohols allows for ring opening to deliver diverse β-functionalized chiral amines.

The current production of bulk chemicals often requires constant high temperatures. Now, Joule heating using electricity can be harnessed by imposing temperature modulation on reactions. By optimizing timescales, reaction selectivity and catalyst stability is improved.

By combining the link of a catenane with the interweaving of a trefoil knot, a molecular structure with a double knot-link containing 14 crossings is prepared. The knot-link contains two homochiral trefoil knots that are quadruply linked with each other.

Scalable and efficient chemical recycling of commodity polymeric materials remains a challenge as the materials continually accumulate in the environment. Now, upcycling of polystyrene into benzoic acid and other value-added chemicals is realized under mild photooxidation conditions, with hydrogen atom transfer as the key step.