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A sustainable C(sp2)–C(sp3) cross-electrophile coupling was developed between readily available 5-bromophthalide and 1-benzyl-4-iodopiperidine under micellar conditions, leading to a key intermediate of one of our development compounds. Copper was found to play a crucial role as a co-catalyst in this dual catalysis system. The chemistry and process were successfully demonstrated in a kilo scale to deliver sufficient drug substance to the clinical campaigns. This is the first reported scale-up of such a challenging cross-electrophilic coupling that uses an aqueous medium, and not undesirable reprotoxic polar aprotic solvents (e.g. DMF, DMAc, and NMP). [ABSTRACT FROM AUTHOR]

Alkynes as unsaturated hydrocarbons have long been used for cyclization reactions. Various transition metal-catalyzed cyclizations of alkynes have been reported in the past decades. In this minireview, we mainly summarize the recent asymmetric cyclization of alkynes with other functional groups such as carbonyl-alkynes, cyano-alkynes, and enynes under the catalytic system of nickel and chiral ligands. [ABSTRACT FROM AUTHOR]

In recent years, with the development of organic synthetic chemistry, a variety of organic synthetic methods have been discovered and applied in practical production. Photochemistry and electrochemistry have been widely used in organic synthesis recently due to their advantages such as mild conditions and green and environmental protection and have now been developed into two of the most massive synthetic strategies in the field of organic synthesis. In order to further enhance the potential of photochemistry and electrochemistry and to overcome the limitations of each, organic synthetic chemists have worked to combine the two synthetic strategies together to develop photoelectrochemistry as a new synthetic method. Photoelectrochemistry achieves the complementary advantages and disadvantages of photochemistry and electrochemistry, avoids the problem of using stoichiometric oxidants or reductants in photochemistry and easy dimerization in electrochemistry, generates highly reactive reaction intermediates under mild conditions, and achieves reactions that are difficult to accomplish by single photochemistry or electrochemistry. This review summarizes the research progress in the field of photoelectrochemistry from the perspective of photoelectro-chemical catalysts in recent years, analyzes the catalytic mechanism of various catalysts in detail, and gives a brief outlook on the research direction and development prospects in this field. [ABSTRACT FROM AUTHOR]

Decellularized extracellular matrix (dECM) nerve guide conduits (NGCs) are a promising strategy to replace autogenous nerve grafting for the treatment of peripheral nerve system (PNS) injury. However, dECM conduits with mechanical properties that match those of peripheral nerves are yet to be well developed. Herein, we developed polyurethane-based NGCs incorporating decellularized spinal cord (BWPU-DSC NGCs) to repair peripheral nerves. BWPU-DSC NGCs have an inner three-dimensional micro–nanostructure. The mechanical properties of BWPU-DSC NGCs were similar to those of polyurethane NGCs, which were proven to promote peripheral nerve regeneration. An in vitro study indicated that BWPU-DSC NGCs could boost the proliferation and growth of cell processes in Schwann and neuron-like cells. In a rat sciatic nerve transected injury model, BWPU-DSC NGCs exhibited a dramatic increase in nerve repair, similar to that obtained by the current gold standard autograft implantation at only 6 weeks post-implantation, whereas polyurethane NGCs still displayed incomplete nerve repair. Histological analysis revealed that BWPU-DSC NGCs could induce the reprogramming of Schwann cells to promote axon regeneration and remyelination. Moreover, reprogrammed Schwann cells together with BWPU-DSC NGCs had anti-inflammatory effects and altered the activation state of macrophages to M2 phenotypes to enhance PNS regeneration. In this study, we provided a strategy to prepare polyurethane-based dECM NGCs enriched with bioactive molecules to promote PNS regeneration. [ABSTRACT FROM AUTHOR]

Diverse, visible-light-induced transformations of methylenecyclopropanes (MCPs) have been reported in recent years, attracting significant attention from synthetic chemists. As readily accessible strained molecules, MCPs have sufficient reactivity to selectively generate different target products, through reactions with various radical species upon visible-light irradiation under regulated reaction conditions. These transformations can be classified into three subcategories of reaction pathway, forming ring-opened products, cyclopropane derivatives, and alkynes. These products include pharmaceutical intermediates and polycyclic/heterocyclic compounds that are challenging to obtain using traditional methods. This review summarizes the recent advancements in this field. [ABSTRACT FROM AUTHOR]

CO2 as a classical C1 unit is often used in the synthesis of high value-added carboxylic acids and their derivatives in organic synthetic chemistry. There have been many reports in the past on electrochemically mediated chemical transformations utilizing electrons as redox reagents. This review will focus on electrocarboxylation methods in the recent 5 years, including metal-mediated electrocarboxylation, direct electrocarboxylation, and some novel electrocarboxylation methods. [ABSTRACT FROM AUTHOR]

The development of metal–organic framework (MOF)-based fluorescent sensors in the detection of metal ions has attracted significant interest. In this study, a novel 2D MOF Tb-DBA was constructed using Tb3+ and 2′-amino-1,1′:4,1′′-terphenyl-4,4′′-dicarboxylic acid (H2DBA) by a solvothermal method. Tb-DBA could detect Al3+, Cr3+ and Fe3+ ions rapidly, sensitively, selectively and reversibly. The detection limit is as low as the nM level. Tb-DBA displayed fluorescence enhancement in the presence of Al3+, Cr3+ and Fe3+ ions. Significantly, Al3+, Cr3+ and Fe3+ ions could be visually detected under UV light. Additionally, Tb-DBA could also act as an indicator for alkaline solutions when pH > 10. The detection mechanism was studied by ICP, EDS and PXRD tests. These studies illustrated that cation exchange proceeded between Tb-DBA and Al3+, Cr3+ and Fe3+ ions, which inhibited the energy transfer from DBA to Tb3+ and enhanced the π*–π transitions of DBA. [ABSTRACT FROM AUTHOR]

The site selective C(sp2)–H bond functionalization of olefins has been achieved through a visible-light-induced photoredox-quinuclidine dual catalysis upon merging the quinuclidinium radical cation addition to alkene strategy and the distal heteroaryl ipso-migration strategy. This synthetic protocol features a simple operation with readily available starting materials in good step-economy to access alkenylheteroaromatic products in moderate to good yields under mild conditions. A plausible cascade catalytic reaction mechanism is also proposed. [ABSTRACT FROM AUTHOR]

A new method for the synthesis of azaaromatic vinylcyclopropanes (VCPs) has been disclosed in this paper by using pyrrole or indole derivatives as nucleophilic reagents to react with vinylidenecyclopropane-diesters (VDCP-diesters) in the presence of a Pd catalyst, a phosphine ligand and a base under mild conditions in up to 98% yield with a reasonable substrate scope. This reaction is one of the few examples of hydroamination at electron-rich allene's β-position. A plausible reaction mechanism has also been proposed through a zwitterionic π-propargyl N-palladium species according to the previous work and the obtained deuterium labeling experimental result. [ABSTRACT FROM AUTHOR]

Carbon dioxide as a classic C1 source has long been investigated in organic synthetic chemistry. Diverse catalytic methods for CO2 activation have been reported over the past several decades. In this minireview, we mainly focus on detailing recent advances (since 2020) in utilizing carbon dioxide to attain the carboxylation of organic motifs via photoredox and metallaphotoredox catalysis. [ABSTRACT FROM AUTHOR]

Lead halide perovskite solar cells (PSCs) have come closer to their commercialization because of their high power conversion efficiencies (PCEs), substantially enhanced stability, and low-cost and scalable manufacturing. However, toxic lead (Pb) as an indispensable component in high-performance PSCs remains an outstanding issue challenging the commercialization of perovskite photovoltaic technology; toxic and water-soluble lead can leak out of perovskite layers under severe weather conditions, resulting in great potential pollution to soil and underground water. It is therefore essential to develop a closed-loop management of lead from preventing Pb leakage from perovskite solar modules during the device service life to recycling Pb from end-of-life modules. Here we highlight the recent advances in the sustainable management of Pb in PSCs from the above two aspects, and provide a brief outlook for the further development of lead management in PSCs. [ABSTRACT FROM AUTHOR]

A ring-opening/cyclization cascade reaction of α-brominated amide-tethered alkylidenecyclopropanes in the presence of photocatalyst 4CzIPN under visible-light irradiation was developed to afford polycyclic benzazepine derivatives in good yields with broad substrate scope and good functional tolerance. A plausible mechanism involving a halogen atom transfer (XAT) process and a radical chain process is proposed for this reaction. This study provides a concise and practical strategy for the synthesis of benzazepine derivatives. [ABSTRACT FROM AUTHOR]

The kinetics of the reactions of tributylphosphine with allenic and olefinic Michael acceptors in dichloromethane at 20 °C was followed by photometric and NMR spectroscopic methods. Combination with DFT-calculated methyl anion affinities revealed the relevance of retroaddition barriers in phosphine-catalysed reactions when mixtures of allenic and olefinic substrates are used. [ABSTRACT FROM AUTHOR]

An interesting type of reaction involving functionalized methylenecyclopropanes (MCPs) has been revealed. Here, a nucleophilic attack of an anionic species onto a partially polarity-reversed MCP was realized by treating a neighbouring carboxylic ester tethered to the MCP and amine with KHMDS to realize an umpolung ring opening of the MCP. This work established an operationally convenient protocol for the rapid construction of isoquinolinone frameworks. [ABSTRACT FROM AUTHOR]

A palladium-catalyzed divergent synthesis of spirooxindoles fused with a five- or a six-membered ring by a cycloaddition reaction of vinylidenecyclopropane-diesters with methyleneindolinones was disclosed. This protocol features an in situ generated unprecedented zwitterionic π-propargyl palladium species in cycloaddition reactions and a switchable process between (3+2) and (4+2) cycloadditions by changing the phosphine ligand. [ABSTRACT FROM AUTHOR]

A silver-catalyzed diastereoselective one-pot domino cyclization-migration/inverse electron-demand oxo-Diels–Alder reaction has been disclosed in this communication through the in situ generated cyclobutane-fused furan intermediate with 4-vinyl-2,3-dioxopyrrolidine for the construction of 2-oxopyrrolidine-fused tricyclic compounds in moderate to good yields with a broad substrate scope under mild conditions. This new synthetic protocol features good efficiency and atom- and step-economy. A plausible reaction mechanism has also been proposed on the basis of previous reports, NMR tracing and control experiments. [ABSTRACT FROM AUTHOR]

A novel Pd/Au vinylene complex synthesized through cyclization of σ,π-heterodinuclear (Pd/Au) acetylide reacted with iodobenzene to give a Pd vinyl species, where the presence of a strong metallophilic Pd⋯Au interaction was found to facilitate phenyl transmetalation from Pd to Au, followed by reductive elimination at Au. [ABSTRACT FROM AUTHOR]

The transformations of cyclopropenes have attracted the attention of organic chemists for decades. As readily accessible strained carbocycles, cyclopropenes show a diverse range of reactivities. This feature article focuses on the developments of cyclopropenes from 2016 until the end of 2019, including reactions through vinylmetal carbenes, reactions through metal complex insertion, addition reactions with 1,3-dipole, radical reactions of cyclopropenes, and reactions of highly reactive in situ generated cyclopropenes. In addition, several new synthetic methods and applications of cyclopropenes are also disclosed in this paper. [ABSTRACT FROM AUTHOR]

Lead-free antiferroelectric (AFE) ceramics have attracted increasing attention in recent years for application in high-power capacitors owing to both environmental friendliness and high energy density. However, the relevant research progress has been seriously restricted by the limited amount of AFE candidate materials with low cost and excellent properties, which significantly rely on the AFE phase stability and crystal symmetry. In this work, NaNbO3–Bi(Mg0.5Ti0.5)O3 (NN–BMT) perovskite solid solutions were reported to obviously exhibit AFE phase structure dependent energy-storage performances, evolving from Wrec ∼ 1.08 J cm−3 and η ∼ 19% at x = 0.05 with an orthorhombic P phase (Pbam) under 25 kV mm−1 to 3.12 J cm−3 and 74%, respectively, at x = 0.08 with an orthorhombic R phase (Pnma) under 30 kV mm−1 owing to the transition of square-like double hysteresis loops into slim and double-like ones and the increased testable electric fields. Most interestingly, doping 0.5 mol% transition-metal oxides (CuO, CeO2 and MnO2) was found to evidently improve the sintering behaviour, bulk resistivity and defect structure, thus leading to largely enhanced dielectric breakdown strength. In particular, the MnO2 doped 0.92NN–0.08BMT sample exhibits a large Wrec of ∼ 5.57 J cm−3 and a high η of ∼ 71% as well as excellent charge–discharge performance (CD = 636.7 A cm−2, PD = 63.7 MW cm−3 and t0.9 ∼ 85 ns), determined by means of the detailed analysis of the grain size distribution, impedance and X-ray photoelectron spectra. The results demonstrate that NN–BMT bulk ceramics could be very competitive lead-free AFE materials for energy-storage capacitors in pulsed power devices. [ABSTRACT FROM AUTHOR]

A gold-catalyzed cascade cyclization of O-tethered 1,7-enynes bearing a cyclopropane moiety has been reported in this communication, affording multi-substituted furans in moderate to good yields. The reaction proceeded through an intramolecular O-nucleophilic addition and 3,3-sigmatropic rearrangement followed by ring-opening of the cyclopropane unit along with the further reaction with electrophiles. The C–C bond cleavage of a strained cyclopropane moiety in the presence of a gold catalyst and the aromatization provided the driving force for this cascade cyclization. The practical transformations of the obtained diiodinated furan have also been indicated. [ABSTRACT FROM AUTHOR]

We herein report a rhodium(iii)-catalyzed cross coupling of indole derivatives with alkylidenecyclopropanes (ACPs) in the presence of KCl, affording the alkene products exclusively with E-selectivity via C–H bond activation. The beta-H elimination to afford the conjugated diene derivatives has been suppressed by the addition of KCl. A plausible reaction mechanism has been proposed along with derivatization of the obtained product to demonstrate the practical usefulness of this synthetic protocol. [ABSTRACT FROM AUTHOR]

A gold(i)-catalyzed highly efficient kinetic resolution of indole–allene derivatives has been demonstrated, providing enantiomerically enriched polycyclic indolines possessing four stereogenic centers including an all-carbon quaternary center in a spirocyclic framework and β-substituted tryptamine derivatives in good to excellent ee values and high s selectivities with good functional group tolerance under mild conditions in an atom-economical way. [ABSTRACT FROM AUTHOR]

A palladium(0)-catalyzed intramolecular transfer hydrogenation and cycloaddition of p-quinamine-tethered alkylidenecyclopropanes (ACPs) to synthesize perhydroindole scaffolds has been reported in this communication. Mechanistic investigations on the basis of deuterium labeling experiments suggest that the reaction proceeded through an oxidative addition of Pd(0) into the distal bond of the ACP moiety to afford a trimethylenemethane (TMM)–Pd intermediate followed by transfer hydrogenation using alcohol. [ABSTRACT FROM AUTHOR]

A catalyst-free intramolecular geminal aminofluorination of ortho-sulfonamide-tethered alkylidenecyclopropanes has been developed. The reaction proceeded through two SET processes with Selectfluor to give a fluorinated cyclopropylcarbinyl cation and a further Wagner-Meerwein rearrangement to generate a cyclobutyl carbocation, which undergoes intramolecular nucleophilic capture by amide to forge fluorinated cyclobuta[b]indoline derivatives. A polycyclic multi-fluorinated byproduct was also formed through a Ritter-type reaction in some cases. [ABSTRACT FROM AUTHOR]