Cooperative Cu/Pd-catalyzed borocarbonylation of ethylene.

We report here a cooperative Cu/Pd-catalyzed multi-component borocarbonylation of ethylene with aryl iodides. A variety of synthetically useful ß-boryl ketones were assembled from the most basic C1 (CO) and C2 (ethylene) building blocks in good yields.

Palladium-Catalyzed Perfluoroalkylative Carbonylation of 2-Allylaryl Trifluoromethanesulfonates: Base-Controlled Selective Access to ß-Perfluoroalkyl Amides.

A palladium-catalyzed perfluoroalkylative carbonylation of 2-allylaryl trifluoromethanesulfonates has been developed. A range of 2-allyl trifluoromethanesulfonates, perfluoroalkyl halides, and amines were applied in this tandem procedure to provide the corresponding ß-perfluoroalkyl amides with good functional group tolerance and high chemoselectivity. The final products were controlled by the base applied.

Non-Noble Metal-Catalyzed Carbonylative Multi-Component Reactions.

Carbonylative multi-component reactions (CMCR), having four or more kinds of starting materials, provide an efficient strategy for the preparation of polyfunctional carbonylated compounds. Diverse CMCR utilizing non-noble transition-metal catalysts have been developed. This review summarized and discussed the recent advances in non-noble metal-catalyzed carbonylative multi-component reactions.

Palladium-Catalyzed Regio- and Stereoselective Hydroaminocarbonylation of Unsymmetrical Internal Alkynes toward α,ß-Unsaturated Amides.

α,ß-Unsaturated amides play a vital role in natural products, pharmaceuticals, organic synthesis, and functional materials. Herein, we disclosed a regio- and stereoselective hydroaminocarbonylation of unsymmetrical internal alkynes via palladium catalysis to synthesize α,ß-unsaturated amides. This protocol features excellent regio- and exclusive (E)-stereoselectivity, high atom and step-economy, broad substrate scope, and functional group tolerance.

Palladium-Catalyzed Desulfonative Carbonylation of Thiosulfonates: Elimination of SO2 and Insertion of CO.

A palladium-catalyzed desulfonative carbonylation of thiosulfonates has been explored. Without any additive, a series of S-aryl/alkyl benzenesulfonothioates were successfully transformed to thioesters in moderate to excellent yields by SO2 extrusion and CO insertion under the pressure of 1 bar of CO. The solvent dimethylacetamide (DMAc) facilitated this desulfonative carbonylation due to its high absorbing ability of SO2.

Cobalt-Catalyzed Four-Component Carbonylation of Methylarenes with Ethylene and Alcohols.

Direct conversion of raw materials to fine chemicals is greatly economically influential. We developed a non-expensive cobalt-catalyzed multicomponent carbonylative reaction for the synthesis of γ-aryl carboxylic acid esters from readily available methylarene, ethylene, and CO, which are widely found in multiple FDA-approved drugs.

Palladium-Catalyzed Carbonylation of Disulfides and Ethylene: Synthesis of ß-Thiopropionate Thioesters.

Transforming carbon monoxide (C1) and ethylene (C2) into high value-added chemicals is of great significance from an economic perspective, especially to multifunctionalized C3 compounds. Herein, we developed a palladium-catalyzed thiocarbonylative 1,2-difunctionalization of ethylene. Employing NiXantPhos as the ligand and DCE as the solvent, a series of organic disulfides can be successfully transformed into ß-thiopropionate thioesters in good yields.

Palladium-Catalyzed Direct Dicarbonylation of Amines with Ethylene to Imides.

The selective and effective conversion of low-cost and simple bulk chemicals into high value-added products through catalytic strategy has a wide range of practical significance. Here, a palladium-catalyzed method for the direct and efficient dicarbonylation of amines with basic industrial feedstock ethylene to imide has been developed. Moderate to excellent yields of the desired imides can be produced from readily available amines in a straightforward manner.

NHC ligand-powered palladium-catalyzed carbonylative C-S bond cleavage of vinyl sulfides: efficient access to tert-butyl arylacrylates.

A method for palladium-catalyzed carbonylative C-S bond activation of divinyl sulfides to synthesize numerous tert-(E)-butyl arylacry-lates under 1 bar of CO has been developed. Employing electron-rich NHC as the ligand, the electron-rich and stabilized palladium complex trend to oxidative addition to the relatively inert C-S bond and decreased the poisoning effect of sulfide and CO; a series of tert-(E)-butyl acrylates were obtained in moderate to good yields.

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.

Ruthenium-Catalyzed Carbonylative Coupling of Anilines with Organoboranes by the Cleavage of Neutral Aryl C-N Bond.

Herein, we report the first ruthenium-catalyzed Suzuki-type carbonylative reaction of electronically neutral anilines via C(aryl)-N bond cleavage. Without any ligand and base, diaryl ketones can be obtained in moderate to high yields by using Ru3(CO)12 as the catalyst and chelation assisted by pyridine. The pyridine ring has a significant effect on both high efficiency and high regioselectivity in the cleavage of the aryl C-N bond in anilines.

Cobalt-Catalyzed Alkoxycarbonylation of Epoxides to ß-Hydroxyesters.

Herein, we developed a new and practical catalytic system for the carbonylative synthesis of ß-hydroxyesters. By using simple, cheap, and air-stable cobalt(II) bromide as the catalyst, combined with pyrazole and catalytic amount of manganese, active cobalt complex can be generated in situ and can catalyze various epoxides to give the corresponding ß-hydroxyesters in moderate to excellent yields. Mechanism studies indicate that pyrazole plays a crucial role in this reaction. Moreover, with the addition of the catalytic amount of manganese, the active cobalt catalyst can be regenerated, which provides a possibility for reusing the cobalt catalyst.

Palladium-Catalyzed Decarboxylative Carbonylative Transformation of Benzyl Aryl Carbonates: Direct Synthesis of Aryl 2-Arylacetates.

A procedure on palladium-catalyzed decarboxylative alkoxycarbonylation of carbonates for the synthesis of aryl 2-arylacetates has been developed. A broad range of aryl 2-arylacetates were obtained in good yields under mild conditions under a carbon monoxide atmosphere. Interestingly, other alcohols can be added as nucleophiles as well, and the corresponding esters were also obtained in good yields.

Phosphite-catalyzed alkoxycarbonylation of aryl diazonium salts.

In this communication, an interesting phosphite-catalyzed alkoxycarbonylation of aryl diazonium salts has been reported. At room temperature and under CO pressure, moderate to good yields of the desired esters can be produced in the absence of bases or any other additives.

Palladium-catalyzed tandem allylic substitution/cyclization and cascade hydrosilylated reduction: the influence of reaction parameters and hydrosilanes on the stereoselectivity.

To shed light on the influence of reaction parameters on palladium-catalyzed tandem allylic alkylation in the presence of Fei-Phos (a chiral trans-1,2-diaminocyclohexane-derived phosphine ligand), the effect of different phosphine ligands, inorganic or organic bases, Brønsted acids, and other additives on the asymmetric palladium-catalysed alkylation of catechol with allylic diacetate was investigated. In this reaction, 2-vinyl-2,3-dihydro-benzo[1,4]dioxin products with promising enantioselectivity were achieved in good yields. In addition, a novel palladium-catalyzed three-component and one-pot allylic substitution/cyclization/reduction reaction assisted by methylphenylsilane was reported with good selectivity.

In situ probing and integration of single self-assembled quantum dots-in-nanowires for quantum photonics.

The realization of fiber-output single photon sources is necessary for quantum photonics. Here we present in situ probing and integration of single self-assembled quantum dots (QDs)-in-nanowires. Single self-assembled AlGaAs QDs were synthesized in GaAs/AlGaAs core-shell nanowires by molecular beam epitaxy and characterized by optical excitation in both micro-PL and fiber-integrating set-up. Cascaded biexciton-exciton emission with a saturation signal of 1000 counts per second at nitrogen temperature is achieved through the fiber-integrating setup, which makes single mode fibers an ideal candidate for single photons sources and paves the way for the realization of 'all fiber' devices. Numerical calculations were carried out to illustrate the collection efficiency and polarized photoluminescence characteristics. Extraction efficiencies as high as 70% over a broadband emission are reported and increase by a factor of about seven in comparison with air extraction, due to the larger refractive index of the fiber core.

Morphological engineering of self-assembled nanostructures at nanoscale on faceted GaAs nanowires by droplet epitaxy.

Fabrication of advanced artificial nanomaterials is a long-term pursuit to fulfill the promises of nanomaterials and it is of utter importance to manipulate materials at nanoscale to meet urgent demands of nanostructures with designed properties. Herein, we demonstrate the morphological tailoring of self-assembled nanostructures on faceted GaAs nanowires (NWs). The NWs are deposited on different kinds of substrates. Triangular and hexagonal prism morphologies are obtained, and their corresponding {110} sidewalls act as platforms for the nucleation of gallium droplets (GDs). We demonstrate that the morphologies of the nanostructures depend not only on the annealing conditions but also on the morphologies of the NWs' sidewalls. Here, we achieve morphological engineering in the form of novel quantum dots (QDs), 'square' quantum rings (QRs), 'rectangular' QRs, 3D QRs, crescent-shaped QRs, and nano-antidots. The evolution mechanisms for the peculiar morphologies of both NWs and nanostructures are modeled and discussed in detail. This work shows the potential of combining nano-structural engineering with NWs to achieve multifunctional properties and applications.

Self-assembled quantum dot structures in a hexagonal nanowire for quantum photonics.

Two types of quantum nanostructures based on self-assembled GaAs quantumdots embedded into GaAs/AlGaAs hexagonal nanowire systems are reported, opening a new avenue to the fabrication of highly efficient single-photon sources, as well as the design of novel quantum optics experiments and robust quantum optoelectronic devices operating at higher temperature, which are required for practical quantum photonics applications.

[Scientific connotation of Chinese medicine refracted in bioenergetics].

The discovery of the electron leak pathways of mitochondrial respiratory chain reveals that the respiratory chain not only included in ATP synthesis through the electron transfer pathway but also included in reactive oxygen species (ROS) generation through the electron leak pathways. The negative effect of ROS is the reason for causing pathological event, but more important is the signaling role of ROS, which had important physiological effect. In this article we take the human body as an aggregate of a huge amount of life-engine and perceive the respiratory chain as "yin-yang" element to describe the modern life science connotation born in the "yin-yang" theory of Chinese medicine.

Redox state of cytochrome c regulates cellular ROS and caspase cascade in permeablized cell model.

In a permeablized cell system, oxidized cyt c is able to induce caspase cascade whereas reduced cyt c cannot. In in vitro experiments, oxidized cyt c can promote H(2)O(2) generation. It is suggested that the redox state of cyt c might regulate the initiation of apoptosis via regulation of cellular ROS level.