Co corrole tethered with an imidazole group at the axial position of the Co ion displays high activity and selectivity for the four-electron reduction of O₂ in alkaline aqueous solutions.

Comprehensive Summary

Developing electrocatalysts with high activity and selectivity for the oxygen reduction reaction (ORR) is vital to promote the performance of the next-generation energy technologies, which depend on the efficiency of the catalytic reduction of dioxygen. In the structure of cytochrome c oxidases (CcOs), a histidine imidazole residue binding to the axial position of Fe plays a crucial role in facilitating the selective reduction of O₂ to water. Inspired by nature, we herein report on the synthesis of Co^III corrole 1 tethered with an imidazole ligand as well as its electrocatalytic ORR and O₂ binding features. As compared to the imidazolium-free analogue, complex 1 displayed remarkably boosted activity for the selective four-electron/four-proton (4e^-/4H⁺) ORR with a half-wave potential of E _1/2 = 0.82 V versus reversible hydrogen electrode (RHE) in 0.1 mol/L KOH solutions. Importantly, we demonstrate that the tethered axial imidazole ligand improves the O₂ binding ability of 1 thermodynamically and dynamically, which is crucial to boost electrocatalytic ORR performance. This work presents an example to improve electrocatalytic ORR activity and selectivity of Co corroles by introducing an axial imidazole ligand to enhance the O₂ binding and activation.

This review summarizes the recent important progress in single-molecule dynamic detections, which are based on electrical-, optical-, as well as the combined approaches.

Comprehensive Summary

Monitoring the dynamics of a single molecule provides unique insights into the fundamental physical and chemical properties of individual molecules. Over the past few decades, various approaches have been developed to enable the real-time and high-resolution detection at the single-molecule level. Among them, electrical and optical methods are the most promising tools, for the reason that electrical detection offers high resolution while optical technology provides non-invasive, targeted measurement with the added benefit of visualization. In this review, we summarized the current state-of-the-art electrical and optical techniques for single-molecule measurement and discussed their applications in detecting dynamic events such as conformational isomerizations, intermolecular interactions, chemical reactions, and biomolecular activities. In addition, we discussed the challenges and opportunities in this area and proposed possible directions for future development.

We developed a novel Pd-catalyzed [4 + 4] cycloaddition of (benzo)furan-derived azadienes with homo-TMM all-carbon 1,4-dipoles in situ generated from α-allyl malonate derivatives, affording an array of benzofuro[3,2-b]azocines and furo[3,2-b]azocines with good to excellent yields (up to 96%) and exclusive regioselectivities. This methodology featured mild reaction conditions and good functional group tolerance. The synthetic utility was demonstrated by a gram-scale reaction. Furthermore, the catalytic asymmetric [4 + 4] cycloaddition version has also been explored.

Comprehensive Summary

We developed a novel Pd-catalyzed [4 + 4] cycloaddition of (benzo)furan-derived azadienes with homo-TMM all-carbon 1,4-dipoles in situ generated from α-allyl malonate derivatives, affording an array of benzofuro[3,2-b]azocines and furo[3,2-b]azocines with good to excellent yields (up to 96%) and exclusive regioselectivities. This methodology featured mild reaction conditions and good functional group tolerance. The synthetic utility was demonstrated by a gram-scale reaction. Furthermore, the catalytic asymmetric [4 + 4] cycloaddition version has also been explored.

Herein, we describe a highly efficient method for site-selective and stereoselective synthesis of potential bioactive 2-amino-2-deoxy-1,3-dithioidoglycosides via organo-catalysis sequential C3-Ferrier rearrangement and Michael addition of 3-O-acetyl-2-nitrogalactals. Both stepwise and one-pot protocols were carried out and work well.

Comprehensive Summary

Idose-type glycosides have numerous biological activities and have been widely used as anticoagulant drugs and anti-infection drugs. Thioglycosides have enhanced stability for acid-mediated or enzymatic hydrolysis, and have a wide range of applications in glycobiology and drug development. Herein, we describe an efficient method for site-selective and stereoselective synthesis of potential bioactive 2-amino-2-deoxy-1,3-dithioidoglycosides via organocatalysis sequential C3-Ferrier rearrangement and Michael addition of 3-O-acetyl-2-nitrogalactals. Both stepwise and one-pot protocols were carried out and work well. This unique thio-glycosylation protocol highlighted the various advantages, including (i) mild reaction conditions; (ii) excellent site-selectivity and stereoselectivity, good to excellent yields; (iii) broad substrate scopes; (iv) being atom-economic and environmentally friendly; (v) the reactions can be scaled up.

Described herein is the difunctionalization of alkenes with BrCF₂CO₂K under photoredox catalysis with the use of a boron-Lewis acid for the access to α,α-difluoro-γ-lactones. This work represents an efficient protocol for the incorporation of CF₂ and lactone units into organic molecules. In this transformation, the alkene substrates and the used reagents, including BrCF₂CO₂K and the boron-Lewis acid, PhB(OH)₂ or BF₃·THF, are cheap and widely available.

Comprehensive Summary

Due to its unique electronic properties, the difluoromethylene group (CF₂) has served as a valuable unity in the design of biologically active molecules. Since γ-lactones display a broad range of biological properties, α,α-difluoro-γ-lactones may exhibit unexpected biological activities, and thus their synthesis has received increasing attention. Traditional synthetic methods suffer from tedious multi- step processes, and very few effective methods have been reported recently. Herein, we describe the difunctionalization of alkenes with BrCF₂CO₂K under photoredox catalysis with the use of a boron-Lewis acid for the access to α,α-difluoro-γ-lactones. In this transformation, the alkene substrates and the used reagents, including BrCF₂CO₂K and the boron-Lewis acid, PhB(OH)₂ or BF₃·THF, are cheap and widely available. High efficiency and atom economy may make this protocol attractive.

This cover picture shows a Co corrole tethered with an imidazole axial group, which displayed remarkably boosted activity for the selective 4e⁻/4H⁺ oxygen reduction reaction (ORR) because of the electronic “push effect” of an axial imidazole ligand. It is shown from experimental results that the tethered axial imidazole ligand improves the O₂ binding ability of Co corroles thermodynamically and dynamically, which is crucial to boost electrocatalytic ORR performance. This work shows the effect of the axial imidazole of Co corroles on O₂ binding and activation and highlights the value of axial ligand tuning on boosted electrocatalytic ORR. More details are discussed in the article by Cao and Lei et al. on page 2866—2872.

This cover picture shows a Co corrole tethered with an imidazole axial group, which displayed remarkably boosted activity for the selective 4e⁻/4H⁺ oxygen reduction reaction (ORR) because of the electronic “push effect” of an axial imidazole ligand. It is shown from experimental results that the tethered axial imidazole ligand improves the O₂ binding ability of Co corroles thermodynamically and dynamically, which is crucial to boost electrocatalytic ORR performance. This work shows the effect of the axial imidazole of Co corroles on O₂ binding and activation and highlights the value of axial ligand tuning on boosted electrocatalytic ORR. More details are discussed in the article by Cao and Lei et al. on page 2866—2872.

Herein, C-aryl glycosylation was established for the synthesis of 2-sulfur C-aryl glycals and 1,2-dihydrobenzofuran-fused C-aryl glycosides via interrupted Pummerer process, featured with sulfonium-tethered [3,3]-sigmatropic rearrangement between sulfoxide glycals and phenols.

Comprehensive Summary

C-aryl glycosides are an important kind of carbohydrate derivatives for drug discovery, due to their distinctive attributes of resistance to hydrolysis from enzymes. Herein, C-aryl glycosylation was established for the synthesis of 2-sulfur C-aryl glycals and 1,2-dihydrobenzofuran-fused C-aryl glycosides via interrupted Pummerer process, featured with sulfonium-tethered [3,3]-sigmatropic rearrangement between sulfoxide glycals and phenols. This protocol offers a broad substrate scope with diverse glycosyl and phenols. Dapagliflozin, Empagliflozin, and Ipragliflozin analogs were straightforward achieved, respectively.

Direct arylation polycondensation (DArP) is an eco-friendly and atom-efficient approach for the synthesis of π-conjugated polymers (CPs). The attainment of efficient and defect-free DArP of thiophene-based C−H monomers is of great importance for the development of high-performance CPs. In this review, we present a mechanistic insight into DArP and describes the development of DArP catalytic systems for varied thiophene-based C−H monomers. More details are discussed in the article by Deng et al. on page 2908—2924.

Direct arylation polycondensation (DArP) is an eco-friendly and atom-efficient approach for the synthesis of π-conjugated polymers (CPs). The attainment of efficient and defect-free DArP of thiophene-based C−H monomers is of great importance for the development of high-performance CPs. In this review, we present a mechanistic insight into DArP and describes the development of DArP catalytic systems for varied thiophene-based C−H monomers. More details are discussed in the article by Deng et al. on page 2908—2924.

Synthesis of C—N axial chirality N-arylindoles via Pd(II)/SPA-catalyzed free amine-directed atroposelective C—H olefination was achieved. A series of C—N axially chiral N-aromatic amine indoles were obtained in high yields with good enantioselectivities (35 examples, up to 91% yield and 96% ee).

Comprehensive Summary

Axially chiral N-arylindoles bearing a stereogenic C—N axis are unique important scaffolds in natural products, advance materials, pharmaceuticals and privileged chiral ligands or catalysts. Herein, we report the direct synthesis of C—N axially chiral N-arylindoles through a Pd-catalyzed free amine-directed atroposelective C—H olefination enabled by a spiro phosphoric acid (SPA) ligand. A wide range of enantioenriched N-aromatic amine indoles were obtained in high yields with good enantioselectivities (35 examples, up to 91% yield and up to 96% ee). The chiral products with free amine group offer an effective functional handle for down-stream diversity-oriented synthesis.

This cover picture shows that the continuously changing surfaces of Dynamic Surface Antifouling (DSAF) materials can effectively prevent microorganisms from landing and adhering. Due to the degradation of the main chain and the hydrolysis of the side chain, the surface renewing is not driven by external force, so the DSAF materials have good antifouling ability even under static conditions. They are also eco-friendly since such degradation yields low molecular weight molecules instead of microplastics. DSAF provides a general strategy to defeat marine biofouling. More details are discussed in the article by Zhang et al. on page 2881—2888.

This cover picture shows that the continuously changing surfaces of Dynamic Surface Antifouling (DSAF) materials can effectively prevent microorganisms from landing and adhering. Due to the degradation of the main chain and the hydrolysis of the side chain, the surface renewing is not driven by external force, so the DSAF materials have good antifouling ability even under static conditions. They are also eco-friendly since such degradation yields low molecular weight molecules instead of microplastics. DSAF provides a general strategy to defeat marine biofouling. More details are discussed in the article by Zhang et al. on page 2881—2888.