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The diversified synthesis of chiral fluorinated cyclobutane derivatives has remained a difficult task in synthetic chemistry. Herein, we present an approach for asymmetric hydroboration and formal hydrodefluorination of gem‐difluorinated cyclobutenes through rhodium catalysis, providing chiral gem‐difluorinated α‐boryl cyclobutanes and monofluorinated cyclobutenes with excellent regio‐ and enantioselectivity, respectively. The key to the success of the two transformations relies on an efficient, mild and highly selective rhodium‐catalyzed asymmetric hydroboration with HBPin (pinacolborane), in which the subsequent addition of a base, and a catalytic amount of palladium in some cases, results in the formation of formal hydrodefluorination products with the four‐membered ring retained. The obtained chiral gem‐difluorinated α‐boryl cyclobutanes are versatile building blocks that provide a platform for the synthesis of enantioenriched fluorinated cyclobutane derivatives to a great diversity. [ABSTRACT FROM AUTHOR]

Olefination of carbonyl compounds is a typical strategy for the synthesis of olefins. Herein, we reported a rhodium‐catalyzed cross‐coupling reaction of ketones with arylboroxines for straightforward access of olefins. The reaction displays a good functional group tolerance and affords the corresponding products in good to excellent yields. Addition and elimination are suggested as the indispensable steps in catalytic cycle by preliminary mechanistic experiments. This reaction provided a complementary method in catalytic construction of olefins from ketones and organoboron compounds. [ABSTRACT FROM AUTHOR]

Cyclobutene scaffolds occur in natural products and bioactive compounds. Their unique structural features and intrinsic ring strain make cyclobutene a type of important building block in synthetic chemistry. In recent years, considerable efforts have been dedicated to the synthesis of chiral cyclobutenes. Enantioselective [2+2] cycloadditions and functionalization of cyclobutene derivatives have emerged as powerful and reliable protocols for achieving this goal, resulting in significant progress in this field. This review provides a comprehensive summary of the recent advancements in the asymmetric synthesis of chiral cyclobutenes, and the discussion is logically divided into four parts according to the reaction mode. [ABSTRACT FROM AUTHOR]

Axial chirality is an interesting stereoisomeric phenomenon in organic chemistry and a key structural feature of several organic compounds. Atropisomers such as biaryls, anilides and diaryl ethers are one type of axially chiral compounds, whose axial chirality is resulted from rotationally blocked single bond. Allenes, spiranes and alkylidenecycloalkanes are another type of axially chiral compounds and their axial chirality come from the perpendicular geometry of two pairs of substituents. The axial chirality in atropisomers, allenes and spiranes has been widely investigated and well developed, while the similar chirality in alkylidene‐cyclic molecules gained very limited attentions. This concept focuses on summarizing recent advances of axial chirality in alkylidene‐cyclic molecules and arouses the research interests to this promising field. [ABSTRACT FROM AUTHOR]

Na3V2(PO4)2F3 with a high theoretical energy density, robust 3D structure, and superior thermal stability has become one of the popular cathode materials for sodium ion batteries. Currently, its poor intrinsic electronic conductivity leads to unsatisfactory rate performance, which is still the bottleneck for commercializing sodium-ion batteries. In this work, carbon nanotube–intertwined Na3V2(PO4)2F3 nanospheres (notated as NVPF@CNTs) are successfully synthesized by a solvothermal method and subsequent heat treatment. In NVPF@CNTs composites, the carbon nanotubes constituted a continuous conductive 3D carbon network, realizing the improvement of electrical conductivity. The NVPF nanospheres are exposed to the electrolyte to increase the contact area with the electrolyte and greatly shorten the diffusion distance of Na+. The unique architecture endorses superior electrochemical performance and good reaction kinetics. Thus, the NVPF@CNTs as cathode exhibits good cycling performance (117.6 mAh g−1 at 0.2 C after 300 cycles) and rate capability (73.4 mAh g−1 at 5 C with a high capacity retention ratio of 91.6% after 600 cycles). The excellent electrochemical performance for NVPF@CNTs opens up a new way to achieve high performance of sodium-ion batteries. [ABSTRACT FROM AUTHOR]

In recent decades, transition-metal-catalyzed nucleophilic dearomatization of electron-deficient heteroarenes, such as pyridines, quinolines, isoquinolines and nitroindoles, has become a powerful method for accessing unsaturated heterocycles. This short review summarizes nucleophilic dearomatizations of electron-deficient hetero-arenes with carbon- and heteroatom-based nucleophiles via transition-metal catalysis. A significant number of functionalized heterocycles are obtained via this transformation. Importantly, many of these reactions are carried out in an enantioselective manner by means of asymmetric catalysis, providing a unique method for the construction of enantio-enriched heterocycles. 1 Introduction 2 Transition-Metal-Catalyzed Nucleophilic Dearomatization of Hetero-arenes via Alkynylation 3 Transition-Metal-Catalyzed Nucleophilic Dearomatization of Heteroarenes- via Arylation 4 Transition-Metal-Catalyzed Nucleophilic Dearomatization of Heteroarenes- with Other Nucleophiles 5 Transition-Metal-Catalyzed Nucleophilic Dearomatization with Nucleophiles Formed In Situ 6 Conclusion and Outlook [ABSTRACT FROM AUTHOR]

Herein, we report a rhodium catalyzed directing‐group free regioselective C−H allylation of simple arenes. Readily available gem‐difluorinated cyclopropanes can be employed as highly reactive allyl surrogates via a sequence of C−C and C−F bond activation, providing allyl arene derivatives in good yields with high regioselectivity under mild conditions. The robust methodology enables facile late‐stage functionalization of complex bioactive molecules. The high efficiency of this reaction is also demonstrated by the high turnover number (TON, up to 1700) of the rhodium catalyst on gram‐scale experiments. Preliminary success on kinetic resolution of this transformation is achieved, providing a promising access to enantio‐enriched gem‐difluorinated cyclopropanes. [ABSTRACT FROM AUTHOR]

Sodium-ion batteries (SIBs) attract extensive attention as a promising alternative to lithium-ion batteries (LIBs) owing to their abundant reserves and low cost for large-scale energy storage systems. Among the electrode materials for sodium ion batteries, Na3V2(PO4)2F3 (NVPF), with the NASICON structure, has a unique three-dimensional (3D) channel, suitable voltage plateau and high thermal stability. However, it suffers from low intrinsic electronic conductivity. In this work, we successfully synthesize hierarchical hollow NVPF@C microspheres assembled from mesoporous nanosheets, and the possible formation process is systematically explored by changing the reaction time, solvent ratio and glucose dosage. At the same time, these microspheres are wrapped in graphene (marked as NVPF@C@rGO) to further improve their electrochemical performance. As a half-cell cathode, the NVPF@C@10 wt% rGO microspheres exhibit excellent rate performance (95 mA h g−1 at 2C) and cycle stability (78.2% capacity retention after 1500 cycles at 5C). This can be attributed to the hierarchical hollow morphology and graphene packages, which provide continuous electron and ion channels, large electrolyte contact areas and stable structures. This work will provide a viable method for designing high-power NIBs. [ABSTRACT FROM AUTHOR]

Based on the strong enhancement effect of procaterol hydrochloride on the electrochemiluminescence (ECL) of Ru(bpy)32+ (bpy = 2,2′-bipyridine) in an alkaline H3PO4-NaOH buffer solution on a bare Pt electrode, a simple, rapid and sensitive method was developed for the determination of procaterol hydrochloride. The optimum conditions for the enhanced ECL have been developed in detail in this work. Under optimum conditions, the logarithmic ECL enhancement vs. the logarithmic concentration of procaterol hydrochloride is linear over a wide concentration range of 2.0 × 10−7 to 2.0 × 10−4 M ( r = 0.9976), with a limit of detection of 1.1 × 10−8 M (S/ N = 3), and a relative standard deviation of 2.1% ( n = 7, c = 5.0 × 10−6 M). The proposed method was applied to the determination of this drug in tablets with recoveries of 89.7%-98.5%. In addition, a possible mechanism for the enhanced ECL of Ru(bpy)32+, which is caused by ProH, has also been proposed. [ABSTRACT FROM AUTHOR]

The Na2MnFe(CN)6 is successfully synthesized by a simple co-precipitation method, and then coated with conducting polymers (PPy) on the surface of Na2MnFe(CN)6 particle. Interestingly, Na2MnFe(CN)6 and Na2MnFe(CN)6@PPy both show hollow octahedral hierarchical structures with nanometer-sized subunits. Na2MnFe(CN)6@PPy exhibits a discharge capacity of 107 mAh•g−1 after 150 cycles at a current density of 10 mA•g−1. It can still remain 65 mAh•g−1 even the current density is increased to 200 mA•g−1. This superior electrochemical property could be ascribed to unique hierarchical architecture as well as improved electronic conductivity. [ABSTRACT FROM AUTHOR]

Cross-coupling reactions involving metal carbene migratory insertion have been established as a new type of coupling reaction with diazo compounds as the reaction partners. Since 2011, an interesting development has been made in which the carbene migratory insertion process is successfully merged into C–H bond activations. Along this line, a series of investigations have been documented in the past few years. This feature article summarizes the developments in this area. [ABSTRACT FROM AUTHOR]

An efficient rhodium(III)-catalyzed synthesis of 2 H-chromene from N-phenoxyacetamides and cyclopropenes has been developed. The reaction represents the first example of using cyclopropenes as a three-carbon unit in rhodium(III)-catalyzed C(sp2)H activations. [ABSTRACT FROM AUTHOR]

A new method for the synthesis offuran-substituted allenes viaCu(I)-catalyzed coupling of conjugated ene-yne-ketones with terminalalkynes has been developed. A wide range of functional groups aretolerated, and the products are obtained in good to excellent yieldsunder mild conditions. A copper carbene migratory insertion is proposedas the key step in this transformation with conjugated ene-yne-ketonesas carbene precursors. [ABSTRACT FROM AUTHOR]

A coupling reaction of N-phenoxyacetamides with N-tosylhydrazones or diazoesters through RhIII-catalyzed CH activation is reported. In this reaction, ortho-alkenyl phenols were obtained in good yields and with excellent regio- and stereoselectivity. Rh-carbene migratory insertion is proposed as the key step in the reaction mechanism. [ABSTRACT FROM AUTHOR]

Palladium-catalyzed reductive coupling reactions between N-tosylhydrazones and aryl halides lead to the formation of C(sp3)–C(sp2) bonds. This approach provides a general route for the synthesis of triarylmethanes. [ABSTRACT FROM AUTHOR]

The mild reaction protocol allows for the preparation of a wide range of furan substituted allenes which may contain various functional groups. [ABSTRACT FROM AUTHOR]

An abstract of the article "Catalyst-Free Cross-Coupling of N-Tosylhydrazones with Chromium(0) Fischer Carbene Complexes: A New Approach to Diarylethanone" is presented.

The article presents chemical equations related to the article "Cu(I)-Catalyzed Coupling of Diaryldiazomethanes with Terminal Alkynes: An Efficient Synthesis of Tri-Aryl-Substituted Allenes" by Chenggui Wu published in the "Tetrahedron" in 2015.

Review: 70 refs. [ABSTRACT FROM AUTHOR]

Review: 32 refs. [ABSTRACT FROM AUTHOR]

The reaction is proposed to proceed by a copper carbene migratory insertion as the key step. [ABSTRACT FROM AUTHOR]

The article presents chemical equations for the article "Palladium-Catalyzed Three-Component Reaction of N-Tosylhydrazone, Norborneneand Aryl Halide" by F. Hu and others published in the journal "Organic & Biomolecular Chemistry" in 2014.

Two procedures for the synthesis of ortho-alkenyl phenols through C-H bond activation are presented. [ABSTRACT FROM AUTHOR]

An abstract of the article "Palladium-Catalyzed Diarylmethyl C(sp3)-C(sp2) Bound Formulation: A New Coupling Approach Toward Triarylmethanes" is presented.

Base-promoted condensation of 1,2-dihaloarenes or 1-halo-2-nitroarenes with 2-sulfanylphenol (II) offers a simple regioselective synthesis of various phenoxathiin structures and aza-analogues such as (XIII) and (XV). [ABSTRACT FROM AUTHOR]

A rhodium-catalyzed olefination of aliphatic aldehydes with arylboroxines is described. The simple rhodium(I) complex [Rh(cod)OH] 2 without any external ligands or additives is able to catalyze the reaction in air and neutral conditions, allowing the construction of aryl olefins in an efficient manner with a good functional group tolerance. The mechanistic investigation illustrates that the binary rhodium catalysis is the key for the transformation, which involves a Rh(I)-catalyzed 1,2-addition and a Rh(III)-catalyzed elimination.

A palladium-catalyzed cross-coupling reaction of cyclobutenone N -tosylhadrazones with organohalides is disclosed. The protocol involves the generation of a strained allylpalladium intermediate from readily available starting materials through palladium carbene migratory insertion, which undergoes electrocyclic ring opening and β-hydride elimination for the production of conjugated enynes and enallenes. The broad substrate scope, good to excellent yields, and tunable product diversity make the protocol potentially useful in organic synthesis.

The exploration of the reactivity of gem -difluorinated small-size rings has continuously drawn attention in recent years but is limited to three-membered carbocycles. Herein we report a copper-catalyzed reaction of gem -fluorinated cyclobutenes with bis(pinacolato)diboron (B 2 pin 2 ). A sequence of defluoroborylation and a ring-opening process produces B,F-bifunctional 1,3-dienes in a stereoselective manner. The transformation together with the efficient downstream coupling of the boronate and the fluoride moieties collectively constitutes a modular route to highly functionalized and stereocontrolled 1,3-dienes.

An efficient protocol for the asymmetric hydroarylation and hydroalkenylation of benzo[ b ]thiophene 1,1-dioxides with organoboranes has been developed. The combination of a rhodium(I) precatalyst and a chiral diene ligand constitutes the catalytic system, which enables the facile synthesis of 2,3-dihydrobenzo[ b ]thiophene 1,1-dioxides in good yields with high enantioselectivities. The merging of this asymmetric hydroarylation with the downstream alkylations delivers 2,3-dihydrobenzo[ b ]thiophene 1,1-dioxides that contain two continuous quaternary stereocenters with high enantioselectivities in a diastereodivergent manner.

Based on the strong enhancement effect of procaterol hydrochloride on the electrochemiluminescence (ECL) of Ru(bpy) 3 2+ (bpy = 2,2'-bipyridine) in an alkaline H 3 PO 4 -NaOH buffer solution on a bare Pt electrode, a simple, rapid and sensitive method was developed for the determination of procaterol hydrochloride. The optimum conditions for the enhanced ECL have been developed in detail in this work. Under optimum conditions, the logarithmic ECL enhancement vs. the logarithmic concentration of procaterol hydrochloride is linear over a wide concentration range of 2.0 × 10 -7 to 2.0 × 10 -4  M (r = 0.9976), with a limit of detection of 1.1 × 10 -8  M (S/N = 3), and a relative standard deviation of 2.1% (n = 7, c = 5.0 × 10 -6  M). The proposed method was applied to the determination of this drug in tablets with recoveries of 89.7%-98.5%. In addition, a possible mechanism for the enhanced ECL of Ru(bpy) 3 2+ , which is caused by ProH, has also been proposed., (Copyright © 2016 John Wiley & Sons, Ltd.)

The synthesis of furan-substituted allenes using conjugated ene-yne ketones as carbene source has been developed. For this reaction, bases play vital roles in controlling the reaction pathways, allowing for access to two types of allene products through trapping of different electrophiles. Mechanistically, the catalytic procedure generated a Cu(I) (2-furyl)carbene intermediate, which is subsequently followed by a migratory insertion process to afford nucleophilic organocopper species. The organocopper species thus generated can be trapped by proton or allyl halide, affording tri- or tetrasubstituted allenes, respectively. The reaction, which is characterized by its mild reaction conditions and the utilization of cheap copper(I) iodide as catalyst, allows for synthesis of a variety of furan-substituted allenes with a wide range of functional groups tolerance.