Copper-Catalyzed Diastereo- and Enantioselective Decarboxylative [3 + 2] Cyclization of Alkyne-Substituted Cyclic Carbamates with Azlactones: Access to γ-Butyrolactams Bearing Two Vicinal Tetrasubstituted Carbon Stereocenters.

A copper-catalyzed diastereo- and enantioselective decarboxylative [3 + 2] cyclization reaction of alkyne-substituted cyclic carbamates with azlactones has been established. A range of optically pure γ-butyrolactams bearing two vicinal tetrasubstituted carbon stereocenters were obtained in high yields with good to excellent stereoselectivities (up to 99% yield, 99:1 dr, and 99% ee). This is the first example of asymmetric synthesis γ-butyrolactams containing sterically congested vicinal tetrasubstituted stereocenters via a decarboxylative cyclization pathway.

A Bifunctional Fluorine-Free Electrolyte Additive for Realizing Dendrite-Free Lithium Anodes.

Owing to the strong energy advantage of lithium anodes, the development of lithium-metal batteries has become an inevitable trend. However, plagued by the instability of solid-electrolyte interphase (SEI) films, lithium metal anodes face challenges such as lithium dendrite formation and volume expansion. Studies have proven that modulating the composition and structure of SEI films by using electrolyte additives is a convenient and valid method.

Ternary PtZrNi nanorods for efficient multifunctional electrocatalysis towards oxygen reduction and alcohol oxidation.

Pt-based alloys with precise structure and composition design have been considered to be effective and robust novel electrocatalysts for fuel cells. Whereas, the sluggish kinetics of oxygen reduction reaction (ORR) and low intrinsic activity of Pt limited their real application on a large scale. Herein, a novel ternary PtZrNi nanorods (PtZrNi NRs) was synthesized via a facile wet-chemical method to achieve high electrocatalytic performance for both ORR and alcohol oxidation reaction owing to the synergism of chosen three elements and prominent one-dimensional morphology.

B(CF)-catalyzed oxidation of α-diazoesters using DMF and molecular oxygen as oxygen sources.

A metal-free catalytic oxidation of α-diazoesters a green environmental-friendly route was developed. The α-diazoesters were converted to α-ketoesters using DMF and molecular oxygen as oxygen sources and B(CF) as the catalyst, without any additives. This protocol has a broad adaptability of substrates and good compatibility with a range of functional groups, and it offers new insight into reactions catalyzed by B(CF).

Advances in image-guided drug delivery for antibacterial therapy.

The emergence of antibiotic-resistant bacterial strains is seriously endangering the global healthcare system. There is an urgent need for combining imaging with therapies to realize the real-time monitoring of pathological condition and treatment progress. It also provides guidance on exploring new medicines and enhance treatment strategies to overcome the antibiotic resistance of existing conventional antibiotics.

Interface-Confined Channels Facilitating Water Transport through an IL-Enriched Nanocomposite Membrane.

Improving the permeance of the polyamide (PA) membrane while maintaining the rejection is crucial for promoting the development of membrane separation technology in the practical water-treatment industry. Herein, a novel metal-ionic liquid (Zn-IL) coordination compound was synthesized by in situ growth to improve the water permeance of PA nanofiltration membranes, using an amine-functionalized IL (1-aminopropyl-3-methylimidazolium chloride, [AEMIm][Cl]) as a ligand to react with Zn(NO)·6HO. Piperazine (PIP) and trimesoyl chloride (TMC) were adopted to prepare the PA layer covering the Zn-IL complex.

Catalytic Enantioselective α-Allylation of Deconjugated Butenolides with Aza-π-allylpalladium 1,4-Dipoles: Access to Optically Pure 2-Piperidones Bearing an All-Carbon Quaternary Stereocenter.

A palladium-catalyzed enantioselective α-allylation of deconjugated butenolides with aza-π-allylpalladium 1,4-diploes, generated from palladium-mediated decarboxylation of cyclic carbamates and amide-substituted acyclic carbonates, has been successfully developed. An array of enantioenriched 2-piperidones bearing an all-carbon quaternary stereocenter were obtained in high yields with excellent enantioselectivities (up to 99% yield and 99% ee). The utility of this method was also showcased by a large-scale reaction and synthetic transformations of the product.

A simulated ecological restoration of bare cut slope reveals the dosage and temporal effects of cement on ecosystem multifunctionality in a mountain ecosystem.

Cement is a critical building material used in the restorations of bare cut slopes. Yet, how cement affects ecosystem's functions and their undertakers remains elusive. Here, we revealed the dosage and temporal effects of cement on plant and soil traits, extracellular enzymes, greenhouse gas fluxes and microbiome using simulation experiments.

Synthesis and properties of high performance thermoplastic polycarbonate polyurethane elastomers through a non-isocyanate route.

Thermoplastic polycarbonate polyurethane elastomers (TPCUEs) are synthesized through a solvent-free non-isocyanate melt polycondensation route. The route starts with the synthesis of 1,6-bis(hydroxyethyloxycarbonylamino)hexane (BHCH) from ethylene carbonate and 1,6-hexanediamine, and then the TPCUEs are prepared by the melt polycondensation of BHCH and polycarbonate diols (PCDLs). The TPCUEs are characterized by GPC, FT-IR, H NMR, XRD, AFM, DSC, TGA and tensile testing.

Organocatalytic asymmetric synthesis of quaternary α-isoxazole-α-alkynyl amino acid derivatives.

An enantioselective addition of 5-amino-isoxazoles with β,γ-alkynyl-α-ketimino esters catalyzed by a chiral phosphoric acid has been developed. This procedure allowed the formation of quaternary α-isoxazole-α-alkynyl amino acid derivatives with high yields (up to 99%) and good to excellent enantioselectivities (up to 97%), and the corresponding products enabled many further elaborations. The control experiment revealed that the hydrogen-bonding interaction of 5-amino-isoxazole with the chiral phosphoric acid played a vital role in the enantioselectivity, and the transition state of the reaction was proposed.

Construction of an Axially Chiral Fluorene Nitrile-Based Framework via Benzannulation of Indene Diene with Benzoylacetonitrile.

The methodology for the synthesis of fluorene-based atropisomers was developed via the strategy of aromatic ring formation. By this strategy, an efficient benzannulation of indene-based diene with benzoylacetonitrile divergently promoted by DABCO and a chiral organocatalyst was established, and various atropisomeric fluorene-based skeletons were generated in good yields, which not only provide a new strategy for the construction of atropisomeric biaryls but also offer a new member to the atropisomeric family.

Zinc Trifluoromethanesulfonate-Catalyzed -Selective Amination of Free Anilines and Free Phenols with Quinoneimides.

An efficient zinc-catalyzed amination of free anilines and free phenols with quinoneimides has been disclosed, which proceeds smoothly under simple and mild conditions. The -selective amination is accomplished on the anilines and phenols via a 1,6-addition pathway, leading to C-N bond formation. The developed protocol offers a promising approach not only for the construction of structurally diverse -phenylenediamine compounds with excellent yields but also for the synthesis of the -amination of free phenol derivatives with good to excellent yields.

Enantioselective Construction of Vicinal Quaternary-Tetrasubstituted Carbon Stereocenters by Copper-Catalyzed Decarboxylative Propargylic Substitution.

Enantioselective construction of vicinal tetrasubstituted carbon stereocenters is a formidable challenge in organic synthesis. A copper-catalyzed asymmetric decarboxylative propargylic substitution with 3-amino oxindoles as trisubstituted carbon nucleophiles and propargylic cyclic carbonates as tertiary carbon electrophiles was developed. A range of 3-amino-3,3'-disubstituted oxindoles bearing vicinal quaternary-tetrasubstituted carbon stereocenters were obtained in high yields and good to excellent stereoselectivities (up to 98% yield, >20:1 dr, and 98.

Catalytic enantioselective hydrophosphinylation of -generated indole-derived vinylogous imines to access 3-(1-diphenylphosphoryl-arylmethyl)indoles.

An efficient organocatalyzed enantioselective hydrophosphinylation of indole-derived vinylogous imines generated from sulfonyl indoles has been developed. Using quinine-derived bifunctional thiourea as the catalyst, a wide range of structurally diverse chiral 3-(1-diphenylphosphoryl-arylmethyl)indoles were obtained with good to excellent results (up to 99% yield and 99% ee). This method represents the first example of the catalytic asymmetric Michael addition of phosphine oxides to vinylogous imine intermediates.

Hyperthermia-induced stellate cell deactivation to enhance dual chemo and pH-responsive photothermal therapy for pancreatic cancers.

For pancreatic ductal adenocarcinoma (PDAC) treatment, the deactivation of pancreatic stellate cells (PSCs) by blocking the transforming growth factor β (TGF-β) pathway is a promising strategy to inhibit stroma, enhance drug penetration, and greatly amplify chemotherapeutic efficacy. It is known that photothermal therapy (PTT) locally depletes stroma and enhances permeability but whether and how PTT reacts in the molecular pathway to induce PSC deactivation in PDAC has rarely been investigated so far. Herein, C-G NPs are synthesized by loading both acid-responsive photothermal molecules and gemcitabine for investigating both the combinatory chemophotothermal therapy and the interaction between the PTT and TGF-β pathway in PDAC.

Multifunctional nanotheranostics for near infrared optical imaging-guided treatment of brain tumors.

Malignant brain tumors, a heterogeneous group of primary and metastatic neoplasms in the central nervous system (CNS), are notorious for their highly invasive and devastating characteristics, dismal prognosis and low survival rate. Recently, near-infrared (NIR) optical imaging modalities including fluorescence imaging (FLI) and photoacoustic imaging (PAI) have displayed bright prospect in innovation of brain tumor diagnoses, due to their merits, like noninvasiveness, high spatiotemporal resolution, good sensitivity and large penetration depth. Importantly, these imaging techniques have been widely used to vividly guide diverse brain tumor therapies in a real-time manner with high accuracy and efficiency.

Engineering of small molecular organic nanoparticles for mitochondria-targeted mild photothermal therapy of malignant breast cancers.

Conventional photothermal therapy (PTT) often causes unwanted hyperthermia damage to the surrounding healthy tissues, and fails in the ablation of infiltrating and malignant tumors, which even leads to tumor recurrence. The main reasons for the suboptimal therapeutic efficacy of PTT include: (i) the heterogenous distribution of PTT agents in cancer cells, (ii) the limited penetration depth of irradiation light, and (iii) importantly, the difficulty in controlling the photothermal process which often leads to overheated hyperthermia and severe side effects, including inflammation, immune escape, metastasis and damage to normal tissues surrounding the tumor. It is envisioned that organelle targeted mild PTT would be a good strategy to overcome these shortcomings and significantly improve the therapeutic efficacy, decrease the therapeutic threshold for both the drug dosage and hyperthermia temperature, and diminish damage to the neighboring healthy tissues.

Preventive effect of surface charge on encrustation of biodegradable ureteral stents.

Prevention of encrustation on the surface has always been the biggest challenge for urological implants. In the field of ureteral stent design, biodegradability has attracted much attention in recent years, because biodegradable ureteral stents not only avoid secondary intervention, but also prevent encrustation due to surface renewal by degradation process. Furthermore, researches have focus on some surface parameters to provide guidance for the development of stent materials, such as hydrophilicity or surface charge.

All-Organic Composite Films for High Flexibility and Giant Nonlinear Optical Limiting Responses.

Given the substantial π-electron delocalization observed in 4--dimethylamino-4--methyl-stilbazolium tosylate (DAST), a high third-order nonlinear optical response can be expected that might manifest itself in various ways for potential applications. To probe the possibility and assess its potential, all-organic DAST-polymethyl methacrylate (PMMA) composite films were prepared by a simple solution casting method, and their nonlinear absorption performances were measured by an open-aperture Z-scan system. The results reveal that under irradiation by a 380 fs laser pulse at 520 nm or a 6 ns laser pulse at 532 nm, the DAST-PMMA composite films with a DAST concentration of 0.

Copper-Catalyzed Decarboxylative Cascade Cyclization of Propargylic Cyclic Carbonates/Carbamates with Pyridinium 1,4-Zwitterionic Thiolates to Fused Polyheterocyclic Structures.

A copper-catalyzed decarboxylative cascade cyclization of propargylic cyclic carbonates/carbamates with pyridinium 1,4-zwitterionic thiolates is developed. A range of fused polyheterocyclic compounds are obtained in moderate to good yields with excellent diastereoselectivities. Of particular note is that four new bonds (two C-C, one C-O/N, one C-S) and four new stereocenters could be efficiently embedded into the tetracyclic fused scaffolds in a single step.

Co-Precipitation Synthesis of Co[Fe(CN)]·10HO@rGO Anode Electrode for Lithium-Ion Batteries.

Rechargeable lithium-ion batteries (LIBs) are known to be practical and cost-effective devices for storing electric energy. LIBs have a low energy density, which calls for the development of new anode materials. The Prussian blue analog (PBA) is identified as being a candidate electrode material due to its facile synthesis, open framework structures, high specific surface areas, tunable composition, designable topologies and rich redox couples.

3D printed PCLA scaffold with nano-hydroxyapatite coating doped green tea EGCG promotes bone growth and inhibits multidrug-resistant bacteria colonization.

Objectives: 3D-printing scaffold with specifically customized and biomimetic structures gained significant recent attention in tissue engineering for the regeneration of damaged bone tissues. However, constructed scaffolds that simultaneously promote bone regeneration and in situ inhibit bacterial proliferation remains a great challenge. This study aimed to design a bone repair scaffold with in situ antibacterial functions.

Copper-Catalyzed Umpolung of -2,2,2-Trifluoroethylisatin Ketimines for the Enantioselective 1,3-Dipolar Cycloaddition with Benzo[]thiophene Sulfones.

A copper-catalyzed umpolung of -2,2,2-trifluoroethylisatin ketimines for the enantioselective 1,3-dipolar cycloaddition with benzo[]thiophene sulfones was developed. Using a catalyst system consisting of an (,)-Bu-Phosferrox ligand, Cu(OTf), and CsCO, a range of pentacyclic spirooxindoles containing pyrrolidine and benzo[]sulfolane subunits were obtained in high efficiency with excellent regio-, diastereo-, and enantioselectivites under mild conditions. The practicality and versatility of the reaction were also demonstrated.

Cu-Catalyzed Asymmetric 1,3-Dipolar Cycloaddition of -2,2,2-Trifluoroethylisatin Ketimines Enables the Desymmetrization of -Arylmaleimides: Access to Enantioenriched FC-Containing Octahydropyrrolo[3,4-]pyrroles.

With a Cu(OTf)/chiral ferrocenyl P,N-ligand complex as a catalyst, the enantioselective desymmetrization of -arylmaleimides was successfully realized by taking advantage of the asymmetric 1,3-dipolar cycloaddition reaction of -2,2,2-trifluoroethylisatin ketimines. A series of structurally diverse FC-containing octahydropyrrolo[3,4-]pyrroles, bearing four contiguous carbon stereocenters and one stereogenic chiral C-N axial bond, were obtained with excellent results (≤99% yield, >20:1 dr, and 99% ee).