Articles in 2022

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  • Reactions induced by σ-aromaticity are uncommon compared with those induced by π-aromaticity. Now, a π- and σ-aromaticity relay strategy is developed to realize the ring contraction of metallacyclobutadiene to metallacyclopropene. This reaction involves the release of π-antiaromaticity to afford a π-aromatic intermediate, followed by ring reclosure to form σ-aromatic metallacyclopropene.

    • Kaiyue Zhuo
    • Yanan Liu
    • Haiping Xia
    Article
  • 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.

    • Norbert Hoffmann
    News & Views
  • Controlling diastereodivergent light-driven processes remains synthetically challenging. Here, we disclose how the light source and steric parameters can be used to control the diastereoselectivity of [2 + 2] heterocycloaddition processes, such as in Paternò–Büchi reactions, and provide access to previously inaccessible stereochemical variants.

    • Javier Mateos
    • Francesco Rigodanza
    • Luca Dell’Amico
    Article
  • 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.

    • Courtney M. Leo
    • Justin G. Kennemur
    News & Views
  • Isolating 2D materials from non-van der Waals (non-vdW) layered structures by mechanical cleavage is challenging owing to strong electronic coupling between adjacent layers. We show that mechanically sliding the layers weakens interlayer interactions, enabling delamination of a wide range of non-vdW layered structures to produce 2D sheets with unusual thickness-dependent physical properties.

    Research Briefing
  • 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.

    • Brett A. Helms
    News & Views
  • Mechanical cleavage of layered materials to obtain two-dimensional (2D) sheets is restricted to materials with interlayer interactions dominated by van der Waals (vdW) forces. Here, calendering is used to weaken interlayer binding in non-vdW layered structures (metals, semiconductors and superconductors) allowing mechanical exfoliation to obtain 2D sheets with thickness-dependent properties.

    • Kun Jiang
    • Jinpeng Ji
    • Fengxia Geng
    Article
  • 1,4-Dicarbonyls are challenging targets owing to the natural-polarity mismatch of potential reaction partners. This Review discusses methods for 1,4-dicarbonyl synthesis based on the coupling of two carbonyl-containing fragments as well as methods that involve non-carbonyl precursors. A spotlight on 1,4-dicarbonyls in total synthesis underlines the diversity of approaches for this motif.

    • Miran Lemmerer
    • Manuel Schupp
    • Nuno Maulide
    Review Article
  • 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.

    • Lei Gong
    News & Views
  • Enantioselective difunctionalization of alkenes mediated with radicals and using selective C–H bond activation remains unexplored. Now, an asymmetric 1,2-oxidative alkylation of conjugated dienes, based on direct functionalization of strong and neutral C(sp3)–H bonds, is reported using a combination of hydrogen atom transfer and copper-catalysed reactions.

    • Lian-Feng Fan
    • Rui Liu
    • Liu-Zhu Gong
    Article
  • 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.

    • Jan H. van Maarseveen
    News & Views
  • 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.

    • Jaclyn Dunn
    • Courtney L. Jenkins
    News & Views
  • 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.

    • Hyeonkyeong Kim
    • Youngdong Yoo
    News & Views
  • Automated organic synthesis is often limited to making simple molecules, requiring a small number of synthetic steps, because of the complexity and variety of organic molecules. Now, a robotic platform has been instructed to build complex structures, such as the core fragment of (+)-kalkitoxin, in a stereochemically controlled and iterative manner.

    • Valerio Fasano
    • Rory C. Mykura
    • Varinder K. Aggarwal
    Article
  • Nucleophiles are versatile reagents that can engage in a plethora of C–C and C–heteroatom bond-forming reactions. This Review examines their increasing role in transition metal-catalysed directed C–H functionalization, with a focus on synthetic approaches involving organometallic nucleophiles and X-based (X = N, O and S) coupling partners.

    • Sergio Barranco
    • Jiayu Zhang
    • Mónica H. Pérez-Temprano
    Review Article
  • A method for the kinetic resolution of diverse planar chiral multisubstituted metallocenes through Rh-catalysed asymmetric C–H arylation of pre-functionalized metallocenes is developed. This general strategy allows for the synthesis of planar chiral 1,2- and 1,3-disubstituted metallocenes bearing a wide range of functional groups.

    Research Briefing
  • Asymmetric C–H functionalisation provides efficient synthetic routes to chiral metallocenes; however, these methods are often limited by the substitution patterns that can be accessed. Now, a Rh-catalysed enantioselective C–H arylation provides access to chiral 1,2-disubstituted and 1,3-disubstituted metallocenes via kinetic resolution of pre-functionalised metallocenes.

    • Chen-Xu Liu
    • Fangnuo Zhao
    • Shu-Li You
    Article
  • Stereoselective alkynylallylic substitution reactions are underexplored compared with propargylic and allylic substitutions. Now, a copper-catalysed intermolecular and decarboxylative alkynylallylic amination, alkoxylation and alkylation strategy has been developed for the synthesis of chiral 1,4-enynes. Mechanistic studies suggest that the formation of a dinuclear copper allenylidene is the rate-limiting step.

    • Jiang-Shan Ma
    • Han-Yu Lu
    • Zhi-Tao He
    Article
  • Torus knots are assembled in a contra-helical tubular manner by coaxially nesting a small multistranded helix within a larger reverse helix. This approach enables the near-quantitative one-step syntheses of four iron(II)-templated trefoil knots. The spin-crossover properties of the iron(II) centres in the knots are tuneable by altering the intramolecular strain.

    • Lin Wu
    • Min Tang
    • Zhichang Liu
    Article