Copper-catalyzed defluorinative arylboration of vinylarenes with polyfluoroarenes.

An unprecedented but challenging defluorinative arylboration has been achieved. Enabled by a copper catalyst, an interesting procedure on defluorinative arylboration of styrenes has been established. With polyfluoroarenes as the substrates, this methodology offers flexible and facile access to provide a diverse assortment of products under mild reaction conditions. In addition, by using a chiral phosphine ligand, an enantioselective defluorinative arylboration was also realized, affording a set of chiral products with unprecedented levels of enantioselectivity.

Matrine suppresses NLRP3 inflammasome activation via regulating PTPN2/JNK/SREBP2 pathway in sepsis.

BACKGROUND: Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Abnormal activation of NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome plays a vital role in the pathogenesis of sepsis. Matrine is proved to show good anti-inflammatory properties, whereas its effect and the underlying molecular machinery on sepsis remains unclear. PURPOSE: The aim of this study is to evaluate the effect and mechanism of Matrine on sepsis. STUDY DESIGN: THP-1 cells and J774A.1 cells were stimulated by lipopolysaccharide (LPS) with nigericin or adenosine triphosphate (ATP) to establish an in vitro model. Cecal ligation and puncture (CLP)-induced sepsis mouse model was used. Matrine was given by gavage. METHODS: To investigate the NLRP3 inflammasome activation, phorbol myristate acetate (PMA)-induced THP-1 cells were first primed with LPS and then stimulated by matrine, followed by treatment with nigericin or ATP. The concentration of interleukin 1ß (IL-1ß) and interleukin 18 (IL-18) in the cell culture supernatant was detected. The mechanism was explored by cell death assay, immunoblots and immunofluorescence in vitro. C57BL/6 mice were intragastrically administered with matrine for 5 days before CLP. The therapeutic effect of matrine was evaluated by symptoms, pathological analysis, ELISA and RT-qPCR. RESULTS: Our results revealed that matrine inhibited IL-1ß and IL-18 secretion, suppressed caspase-1 activation, reduced cell death, and blocked ASC speck formation upon NLRP3 inflammasome activation. Furthermore, matrine restrains NLRP3 inflammasome activation as well as pyroptosis through regulating the protein tyrosine phosphatase non-receptor type 2 (PTPN2)/JNK/SREBP2 signaling. Matrine also prominently improved the symptoms and pathological changes with reduced levels of TNF-α, IL-1ß, and IL-6 in the lung tissues and serum in a dose-dependent manner. CONCLUSION: Matrine effectively alleviates the symptoms of CLP-induced sepsis in mice, restrains NLRP3 inflammasome activation by regulating PTPN2/JNK/SREBP2 signaling pathway, and may become a promising therapeutic agent for sepsis treatment.

Copper-Catalyzed Boroaminomethylation of Olefins to γ-Boryl Amines with CO as C1 Source.

Boroaminomethylation of olefins is an efficient process to convert hydrocarbons directly into boron-, nitrogen-containing molecules. Such chemicals are a good handle for obtaining more complexed amine derivatives through the various transformations of organoboron. However, using simple and easily available CO as the C1 feedstock to achieve boroaminomethylation is still elusive. Here we report a copper-catalyzed boroaminomethylation of olefins with CO as the C1 source via the mechanism of a carbene insertion into the N-H bond. This method affords valuable γ-boryl amines from four inexpensive readily chemicals. The wide synthetic transformations of the γ-boryl amines demonstrates their utility. Notably, 13 C labeling studies revealed that the -CH2 -building block was derived from one molecule of CO.

Catalyst-controlled selective borocarbonylation of benzylidenecyclopropanes: regiodivergent synthesis of γ-vinylboryl ketones and ß-cyclopropylboryl ketones.

Regioselective catalytic multi-functionalization reactions enable the rapid synthesis of complexed products from the same precursors. In this communication, we present a method for the regiodivergent borocarbonylation of benzylidenecyclopropanes with aryl iodides. Various γ-vinylboryl ketones and ß-cyclopropylboryl ketones were produced in moderate to good yields with excellent regioselectivity from the same substrates. The choice of the catalyst is key for the regioselectivity control: γ-vinylboryl ketones were produced selectively with IPrCuCl and Pd(dppp)Cl2 as the catalytic system, while the corresponding ß-cyclopropylboryl ketones were obtained in high regioselectivity with Cu(dppp)Cl, [Pd(η 3-cinnamyl)Cl]2 and xantphos as the catalytic system. Moreover, γ-vinylboryl ketones and ß-cyclopropylboryl ketones were successfully transformed into several other value-added products.

Copper-catalyzed borofunctionalization of styrenes with B2pin2 and CO.

The construction of structurally complexed and high-value chemical molecules from simple and readily available feedstocks is a long-standing challenge to chemists. Here, we describe a copper-catalyzed borofunctionalization of styrenes with B2pin2 and carbon monoxide. A set of new sodium cyclic borates were obtained with NaO t Bu as the base. These unique sodium cyclic borates can be easily converted into a variety of multifunctional ß-boryl vinyl esters, boryl carbonates, ß-boryl aldehydes, and boryl vinyl ether. In addition, the procedure also features good functional group tolerance and utilizes CO as the C1 source.

Copper-Catalyzed 1,2-Trifluoromethylation Carbonylation of Unactivated Alkenes: Efficient Access to ß-Trifluoromethylated Aliphatic Carboxylic Acid Derivatives.

A novel copper-catalyzed carbonylative trifluoromethylation of unactivated alkenes has been developed. A broad range of ß-trifluoromethylated carboxylic acid derivatives were prepared in moderate to excellent yields from simple alkenes with excellent regioselectivity. It is noteworthy that ethylene gas, as the simplest olefin, can also be applied directly to obtain ß-trifluoromethylated amides and ester. This transformation presents the first example on carbonylative trifluoromethylation of alkenes.

Pd/Cu-Catalyzed amide-enabled selectivity-reversed borocarbonylation of unactivated alkenes.

The addition reaction between CuBpin and alkenes to give a terminal boron substituted intermediate is usually fast and facile. In this communication, a selectivity-reversed procedure has been designed and established. This selectivity-reversed borocarbonylation reaction is enabled by a cooperative action between palladium and copper catalysts and proceeds with complete regioselectivity. The key to the success of this transformation is the coordination of the amide group and slower CuBpin formation by using KHCO3 as the base. A wide range of ß-boryl ketones were produced from terminal unactivated aliphatic alkenes and aryl iodides. Further synthetic transformations of the obtained ß-boryl ketones have been developed as well.

Copper-Catalyzed Borylative Methylation of Alkyl Iodides with CO as the C1 Source: Advantaged by Faster Reaction of CuH over CuBpin.

CuH and CuBpin are versatile catalysts and intermediates in organic chemistry. However, studies that involve both CuH and CuBpin in the same reaction is still rarely reported due to their high reactivity. Now, a study on CuH- and CuBpin-catalyzed borylative methylation of alkyl iodides with CO as the C1 source is reported. Various one carbon prolongated alkyl boranes (RCH2 Bpin and RCH(Bpin)2 ) were produced in moderate to good yields from the corresponding alkyl iodides (RI). In this cooperative system, CuH reacts with alkyl iodide faster than CuBpin.

Pd/Cu-Catalyzed Defluorinative Carbonylative Coupling of Aryl Iodides and gem-Difluoroalkenes: Efficient Synthesis of α-Fluorochalcones.

An unprecedented and challenging defluorinative carbonylation was achieved. Enabled by a Pd/Cu cooperative catalyst system, the first example of defluorinative carbonylative coupling has been established. With gem-difluoroalkenes and aryl iodides as the substrates, this methodology offers flexible and facile access to privileged α-fluorochalcones under mild reaction conditions in moderate-to-excellent yields. Mechanistic studies indicated transmetalation between palladium and copper intermediates as a crucial step of the catalytic cycle.

Ligand-Controlled Copper-Catalyzed Regiodivergent Carbonylative Synthesis of α-Amino Ketones and α-Boryl Amides from Imines and Alkyl Iodides.

Regioselective transformation is among the long-standing challenges in organic synthesis. In this communication, a copper-catalyzed selectivity controlled regiodivergent borocarbonylation of imines with alkyl iodides has been developed. Various α-amino ketones and α-boryl amides were produced in moderate to good yields from the same substrates. The choice of the ligand is key for the regioselectivity control: α-amino ketones were produced selectively in good yields with (p-CF3 C6 H4 )3 P as the ligand, whereas the corresponding α-boryl amides were obtained with high regioselectivities when using Me IMes as the ligand.

Copper-Catalyzed Carbonylative Hydroamidation of Styrenes to Branched Amides.

Amides are one of the most ubiquitous functional groups in synthetic and medicinal chemistry. Novel and rapid synthesis of amides remains in high demand. In this communication, a general and efficient procedure for branch-selective hydroamidation of vinylarenes with hydroxyamine derivatives enabled by copper catalysis has been developed for the first time. The reaction proceeds under mild conditions and tolerates a broad range of functional groups. Applying a chiral phosphine ligand, an enantioselective variant of this transformation was achieved, affording a variety of chiral α-amides with excellent enantioselectivities (up to 99 % ee) and high yields.

Copper-Catalyzed Synthesis of Stereodefined Cyclopropyl Bis(boronates) from Alkenes with CO as the C1 Source.

A novel copper-catalyzed stereodefined procedure for the selective synthesis of cyclopropyl bis(boronates) from terminal alkenes has been developed. Various aliphatic alkenes were transformed into the desired bis(boronate ester)-substituted cyclopropanes in moderate to good yields. Synthetic transformations of the resulting cyclopropyl bis(boronates) demonstrate their utility. A possible reaction mechanism is proposed.

Four-Component Borocarbonylation of Vinylarenes Enabled by Cooperative Cu/Pd Catalysis: Access to ß-Boryl Ketones and ß-Boryl Vinyl Esters.

We report here a general four-component synthetic procedure for the preparation of ß-boryl ketones and ß-boryl vinyl esters. Joint catalyzed by palladium and copper catalysts, borocarbonylative reaction between vinylarenes, aryl halides/triflates, B2 Pin2 , and carbon monoxide proceed successfully. A variety of synthetically useful ß-boryl ketones were synthesized in good to high yields by using aryl iodides as the substrates. It is noteworthy that when aryl triflates were applied as the starting materials, ß-boryl vinyl esters were synthesized in a similar manner and with broad functional group tolerance. A rational mechanism for this reaction was also proposed.

Copper-Catalyzed Regioselective Borocarbonylative Coupling of Unactivated Alkenes with Alkyl Halides: Synthesis of ß-Boryl Ketones.

The borocarbonylative coupling of unactivated alkenes with alkyl halides remains a challenge. In this communication, a Cu-catalyzed borocarbonylative coupling of unactivated alkenes with alkyl halides for the synthesis of ß-boryl ketones has been developed. A broad range of ß-boryl ketone derivatives was prepared in moderate to excellent yields with complete regioselectivity.

Carbonylative Transformation of Allylarenes with CO Surrogates: Tunable Synthesis of 4-Arylbutanoic Acids, 2-Arylbutanoic Acids, and 4-Arylbutanals.

In this Communication, procedures for the selective synthesis of 4-arylbutanoic acids, 2-arylbutanoic acids, and 4-arylbutanals from the same allylbenzenes have been developed. With formic acid or TFBen as the CO surrogate, reactions proceed selectively and effectively under carbon monoxide gas-free conditions.

Palladium-Catalyzed Tunable Carbonylative Synthesis of Enones and Benzofulvenes.

A palladium-catalyzed four-component carbonylative coupling reaction involving aryl halides, internal alkynes, arylboronic acids, and CO has been developed for the first time. All-carbon substituted α-unsaturated ketones and benzofulvenes can be selectively obtained in a highly regio- and stereocontrolled manner. Using Cu(TFA)2 as the additive, a series of tetrasubstituted α-unsaturated ketones were prepared in moderate to high yields. Using more acidic Lewis acid Cu(OTf)2 as the additive, multisubstituted benzofluvenes were synthesized in moderate yields. This efficient methodology involved the formation of three new C-C bonds, and provided a divergent method for the quick construction of multisubstituted α-unsaturated ketones and benzofulvenes from easily available starting materials.

Deep-Blue and Hybrid-White Organic Light Emitting Diodes Based on a Twisting Carbazole-Benzofuro[2,3-b]Pyrazine Fluorescent Emitter.

A novel deep-blue fluorescent emitter was designed and synthesized. The external quantum efficiency (ηEQE) of the blue-emitting, doped, organic light-emitting diode (OLED) was as high as 4.34%. The device also exhibited an excellent color purity with Commission Internationale de l'Eclairage (CIE) coordinates of x = 0.15 and y = 0.05. In addition, the triplet energy had a value of 2.7 eV, which is rare for an emitter with deep-blue emission, which makes it a preferred choice for high-performance white OLEDs. By optimizing the device architectures, the color of hybrid-white OLEDs could be tunable from warm white to cool white using the aforementioned material as a bifunctional material. That is, the ηEQE of the hybrid warm-white OLED is 20.1% with a CIE x and y of 0.46 and 0.48 and the ηEQE of the hybrid cool-white OLED is 9% with a CIE x and y of 0.34 and 0.33.

First-Row Transition-Metal-Catalyzed Carbonylative Transformations of Carbon Electrophiles.

The main contributions in the field of first-row transition-metal-catalyzed (base-metal-catalyzed) carbonylative transformations have been summarized and discussed. The contents have been divided according to the electrophiles applied, followed by the different types of nucleophiles. Their reaction mechanisms and applications have been emphatically discussed.

Nickel-Catalyzed Carbonylative Synthesis of Functionalized Alkyl Iodides.

Functionalized alkyl iodides are important compounds in organic chemistry and biology. In this communication, we developed an interesting nickel-catalyzed carbonylative synthesis of functionalized alkyl iodides from aryl iodides and ethers. With Mo(CO)6 as the solid CO source, both cyclic and acyclic ethers were activated, which is also a challenging topic in organic synthesis. Functionalized alkyl iodides were prepared in moderate to excellent yields with outstanding functional group tolerance. Besides the high value of the obtained products, all the atoms from the starting materials were incorporated in the final products and the reaction had high atom efficiency as well.

Near-Infrared Ternary Tandem Solar Cells.

The paucity of near-infrared (NIR) organic materials with high absorption at long wavelengths, combined with large diffusion lengths and charge mobilities, is an impediment to progress in achieving high-efficiency organic tandem solar cells. Here a subcell is employed within a series tandem stack that comprises a solution-processed ternary blend of two NIR-absorbing nonfullerene acceptors and a polymer donor combined with a small-molecular-weight, short-wavelength fullerene-based subcell grown by vacuum thermal evaporation. The ternary cell achieves a power conversion efficiency of 12.6 ± 0.3% with a short-circuit current of 25.5 ± 0.3 mA cm-2 , an open-circuit voltage of 0.69 ± 0.01 V, and a fill factor of 0.71 ± 0.01 under 1 sun, AM 1.5G spectral illumination. The success of this device is a result of the nearly identical offset energies between the lowest unoccupied molecular orbitals (LUMOs) of the donors with the highest occupied molecular orbital (HOMO) of the acceptor, resulting in a high open-circuit voltage. A tandem structure with an antireflection coating combining these subcells demonstrates a power conversion efficiency of 15.4 ± 0.3%.