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The difluoromethylation of N-arylsulfonyl hydrazones with difluorocarbene generated from difluoromethylene phosphobetaine (Ph3P+CF2CO2−) to give various difluoromethyl aryl sulfones is described.

Facile carbocation-initiated [4+2] cycloaddition of o-anisole-substituted propargyl silyl ethers and ynamides led to the formation of 4-vinylcoumarins. Subsequent intramolecular cyclization of 3-aryl-4-vinylcoumarins afforded polycyclic coumarin derivatives 11,12-dihydronaphtho[1,2-c]chromen-5-ones in excellent yields under mild photo-irradiated conditions established by fluorescence analysis-oriented screening.

Phellibarin D ( 1 ), the first B/C ring-rearranged lanostane triterpenoid possessing a 6/5/7/5 ring framework, was isolated from Phellinus rhabarbarinus . This compound’s structure was determined via comprehensive NMR and MS analyses. In addition, 1 exhibited cytotoxicity against five human cancer cell lines and inhibitory activity against nitric oxide (NO) production in LPS-activated RAW264.7 macrophages.

The mechanism-oriented reaction design for the divergent synthesis of chiral molecules from simple starting materials is highly desirable. In this work, aromatic amide-derived nonbiarylatropisomer/silver (silver/Xing-Phos) complex was used to catalyze the Michael addition of glycine aldimino esters to chalcones and successfully applied to the subsequent cyclocondensation to afford substituted cis-Δ(1)-pyrroline derivatives with up to 98 % ee. Besides the inherent performance of the chiral Ag/Xing-Phos catalyst system, it was found that the workup of such reactions played an important role for the stereoselective construction of stereodivergent Δ(1)-pyrrolines, in which an epimerization of the cis-Δ(1)-pyrrolines to the trans-isomers during was revealed.

It was found that the catalytic Huisgen cycloaddition reaction of succinimide-derived bisalkynes with azides resulted in useful succinimide-derived triazoles bearing quaternary carbon-stereogenic centers with good to excellent yields as well as good chemoselectivity and moderate to high enantioselectivities (up to 97% ee), in which the CuF2/Tao-Phos complex was proved to be an effective bimetallic catalyst in the presence of triethylamine. The mechanistic studies based on the effect of reaction parameters on stereoselectivity as well as ESI-MS analysis suggested that our ligand (Tao-Phos) and related binuclear copper centers play a crucial role in this asymmetric click chemistry because of the strong catalyst–substrate interaction with the aid of a possibly in situ formed binuclear or multinuclear copper-based transition state. This work not only provides a new example of a Cu(II)-mediated asymmetric AAC reaction involving chelating base and azides, but also suggests the significance of binuclear copper species in catalytic asymmetric click reactions with two copper center-involved enantioselective inductions.

The vastly increasing application of chiral Cp ligands in asymmetric catalysis results in growing demand for novel chiral Cp ligands. Herein, we report a new class of chiral Cp ligands based on 1,1'-spirobiindane, a privileged scaffold for chiral ligands and catalysts. The corresponding Rh complexes are shown to be excellent catalysts in asymmetric oxidative coupling reactions, providing axially chiral biaryls in 19-97% yields with up to 98:2 er.

To shed light on the scope and limitations of palladium-catalyzed allylic alkylation in the presence of chiral trans-1,2-diaminocyclohexane-derived Fei-Phos as an effective phosphine ligand, the asymmetric palladium-catalysed alkylation of structurally diverse hard/soft nucleophiles, including allylic etherification of alcohols and the allylic alkylation of activated methylene compounds, indoles, and aromatic amines were investigated in this study; the corresponding products with various functional groups were achieved in good yield and with high enantioselectivity (up to 99% ee).

The conventional etherification uses toxic or hardly degradable alkylating agents. An eco-friendly tandem etherification/aromatization is presented to prepare estrone 3-secondary ethers from easily available dienone 1. Three marketed 3-etherified estrogen drugs were synthesized with the method from commercial available starting material.

A series of 2,3-substituted-2-iminothiazoline-4-ones derivatives have been synthesized via an improved method including an auto-catalyzed reaction. This method avoided using any extra catalyst except for the reaction material. This method has been successful in both the aromatic substituted 2-iminothiazolines and the alkyl substituted 2-iminothiazolines. The special product with a hydroxyl group on the 2-iminogroup of 1,3-thiazoline-4-ones has also been obtained unexpectedly. The possible mechanism has been proposed for the special process of dealkylation and hydroxylation. This method offered a special way to afford the 2-hydroxyimino-substituted thiazoline-4-one derivatives in an efficient and eco-friendly way. The mechanism of the transformation under acid condition has also been proposed.

Cross-coupling between difluorocarbene and carbene-derived intermediates generated from diazocompounds was developed to give gem-difluoroolefins, which constitutes a fast practical pathway to achieve hindered gem-difluoroolefins. The cross-coupling between difluorocarbene and aryl diazoacetates proceeded smoothly in the presence of a copper source, whereas its coupling with diaryl diazomethanes occurred well under metal-free conditions. A mechanism involving a copper–difluorocarbene complex was proposed.

The Cu(I)-catalyzed azide-alkyne cycloaddition reaction, also known as click chemistry, has become a useful tool for the facile formation of 1,2,3-triazoles. Specifically, the utility of this reaction has been demonstrated by the synthesis of structurally diverse bi- and bis-1,2,3-triazoles. The present review focuses on the synthesis of such bi- and bistriazoles and the importance of using copper-promoted click chemistry (CuAAC) for such transformations. In addition, the application of bitriazoles and the related CuAAAC reaction in different fields, including medicinal chemistry, coordination chemistry, biochemistry, and supramolecular chemistry, have been highlighted.

A highly efficient N,N′-dioxide–Zn(II) complex catalytic system for the asymmetric Diels–Alder reaction of Brassard-type diene with methyleneindolines was developed. The optically pure spiro[cyclohex[3]ene-1,3′-indoline]-1′-carboxylate-2, 2′-dione derivatives containing three stereocenters were obtained in moderate yields with 98% to >99% ee in a stereospecific manner.

Triarylmethanes and diarylalkanes are synthesized by the title method under mild reaction conditions in high yields.

An efficient strategy towards triazole- or phosphine-oxide-substituted alkynes with the assistance of strong base LiHMDS is described. The facile and practical reaction took place from easily prepared substrates in a one-pot manner without participation of any transition metal catalysts or ligands, exhibiting good functional groups tolerance (up to 37 examples) and high efficiency (up to 90% yields). The isolation of the key intermediate proved the hypothesis of the proposed mechanism of the one-pot preparation.

A copper-catalyzed phosphorylation of coumarins has been developed. Different from previous reports, this catalytic system involved the use of copper as a catalyst and trialkyl phosphonates as phosphorus sources with moderate to good yields, which provides an alternative way to prepare coumarins containing phosphates.

Heterogeneous selective hydrogenation plays an important role in the manufacture of high value-added chemicals. Modification of noble metal catalysts, e.g. Pd, Pt and Au, by using inorganic or organic compounds has been emerging as one of the most effective strategies to enhance the substrate selectivity, chemoselectivity, and enantioselectivity as well. The purpose of this paper is to review recent experimental and theoretical advances on this topic. We will concentrate on the steric and/or electronic effects at the surface/interface induced by the surface molecular modifiers, and how these effects work alone or together to generate a high selectivity.

A novel 6H-type hexagonal perovskite Ba3(Cr0.97(1)Te0.03(1))2TeO9 was prepared at high pressure (6 GPa) and temperature (1773 K). Both transmission electron microscopy and synchrotron powder X-ray diffraction data demonstrate that Ba3(Cr0.97(1)Te0.03(1))2TeO9 crystallizes in P63/mmc with face-shared (Cr0.97(1)Te0.03(1))O6 octahedral pairs interconnected with TeO6 octahedra via corner-sharing. Structure analysis shows a mixed Cr2+/Cr3+ valence state with ∼10% Cr2+. The existence of Cr2+ in Ba3(Cr2+0.10(1)Cr3+0.87(1)Te6+0.03)2TeO9 is further evidenced by X-ray absorption near-edge spectroscopy. Magnetic properties measurements show a paramagnetic response down to 4 K and a small glassy-state curvature at low temperature. In this work, the octahedral Cr2+O6 component is stabilized in an oxide material for the first time; the expected Jahn–Teller distortion of high-spin (d4) Cr2+ is not found, which is attributed to the small proportion of Cr2+ (∼10%) and the face-sharing arrangement of CrO6 octahedral pairs,...

Metal-halide perovskites have been hailed as remarkable materials for photovoltaic devices and, recently, their star has also been on the rise in optoelectronics and photonics. In particular, the optical properties of a metal-halide perovskite can be widely manipulated once its bulk structure has been reduced to a low-dimensional structure, allowing multiple functionalities of light generation, emission, transmission, and detection to be realized in one material. In this paper, we highlight the recent advances in the synthesis of low-dimensional metal-halide perovskites and their unique properties as well as their novel optoelectronic and photonic applications. It is anticipated that this review can serve as an overview and evaluation of state-of-the-art synthesis techniques as well as nanoscale optoelectronics and photonics based on low-dimensional perovskite nanocrystals.

A one-pot acid-mediated reaction has been developed for the N–H/α,β-C(sp3)–H trifunctionalization of pyrrolidine without any metallic reagents or external oxidants. This reaction involves the intermolecular [3 + 2] cycloaddition of in situ-generated azomethine ylides with acrylic esters to provide facile access to 2,3-dihydro-1H-pyrrolizine derivatives in high yields under mild conditions.

A mild Zn-catalyzed intermolecular Diels–Alder/ene tandem reaction with styrene as a 4π-component is reported. A variety of dihydronaphthalene products could be prepared in moderate to good yields. Moreover, a combination of DFT calculations and experiments was performed to further understand the mechanism of this unique tandem reaction.

A transition-metal-free coupling annulation reaction of arynes, ketones, and alkynoates has been demonstrated. Using this formal [2 + 2 + 2] cycloaddition reaction, a wide variety of naphthalene derivatives were conveniently constructed in one pot with high efficiency. In addition, this novel and valid annulation has been successfully applied to the synthesis of 1-phenanthrenol derivatives.

The development of a highly enantioselective catalytic oxa-Pictet–Spengler reaction has proven a great challenge for chemical synthesis. We now report the first example of such a process, which was realized by utilizing a nitrated confined imidodiphosphoric acid catalyst. Our approach provides substituted isochroman derivatives from both aliphatic and aromatic aldehydes with high yields and excellent enantioselectivities. DFT calculations provide insight into the reaction mechanism.

A series of Nb—W—Ln heterometallic polyoxometalates {Ln12W12O36(H2O)24 (Nb6O19)12} (Ln: Y, La, Sm, Eu, Yb) is prepared by e.g. hydrothermal reaction of K7HNb6O19, Na2WO4, Cu(OAc)2, SmCl3, trimesic acid, and en in a carbonate buffer at pH 10.5 (autoclave, 160 °C, 72 h, 70% yield).

The reaction works well with aryl arylpropiolates Phenyl tert-butylpropiolate does not react.

A pyridinebis(oxazoline) cobalt complex is a very efficient precatalyst for the hydrosilylation of terminal alkynes with Ph2 SiH2 , providing α-vinylsilanes with high (Markovnikov) regioselectivity and broad functional-group tolerance. The vinylsilane products can be further converted into geminal borosilanes through Markovnikov hydroboration with pinacolborane and a bis(imino)pyridine cobalt catalyst.

A novel azidative cycloisomerization of homoallenyl amides (I) and (III) using TmsN3 as the azidation reagent and a hypervalent iodine reagent as the oxidant giving a series of azidomethyl-furans (II) and (IV), resp., is presented.

Chiral o -aniline sulfoxides serving as chiral sulfurous source were synthesized, from which new sulfonamide-pyridine ligands were made in three-steps. These compounds proved to be efficient S , N -ligands for enantiocontrol of palladium-catalyzed allylic substitutions of dimethyl 2-fluoromalonate. The induced effect of the Pd/ S , N -ligand catalyst on the enantioselectivity depends on the steric demand of the substituent on the sulfoxide moiety. This method provided the fluorine-containing allylic products with up to 94% ee .

A nucleophilic addition/cyclization/aromatization cascade of aromatic alkenes/alkynes, trimethylsilyl cyanide, and N,N-disubstituted formamides gives pyrroles in moderate to good yields with high regioselectivities.

New layered honeycomb tellurates, BiM(III)TeO6 (M = Cr, Mn, Fe) were synthesized and characterized. BiM(III)TeO6 (M = Cr, Fe) species crystallize in a trigonal space group, P31c (No. 163), of edge-sharing M3+/Te6+O6 octahedra, which form honeycomb-like double layers in the ab plane with Bi3+ cations located between the layers. Interestingly, the structure of BiMnTeO6 is similar to those of the Cr/Fe analogues, but with monoclinic space group, P21/c (No. 14), attributed to the strong Jahn–Teller distortion of Mn3+ cations. The crystal structure of BiM(III)TeO6 is a superstructure of PbSb2O6-related materials (ABB′O6). The Cr3+ and Fe3+ cations are ordered 80% and 90%, respectively, while the Mn3+ ions are completely ordered on the B-site of the ABB′O6 structure. BiCrTeO6 shows a broad antiferromagnetic transition (AFM) at ∼17 K with a Weiss temperature (θ) of −59.85 K, while BiFeTeO6 and BiMnTeO6 show sharp AFM transitions at ∼11 K with θ of −27.56 K and at ∼9.5 K with θ of −17.57 K, respectively. These d...

ConspectusCascade reactions represent a class of ideal organic reactions because they empower efficiency, elegance, and novelty. However, development of cascade reactions remains a daunting task for synthetic chemists. Radicals are known to be well suited for cascade reactions. Compared with widely used carbon-based radicals, nitrogen-based radicals, such as neutral aminyl radicals and protonated aminyl radicals (amine radical cations), are underutilized, although they are behind some notable synthetic methods such as the Hofmann–Loffler–Freytag reaction. The constraint on their usage is generally attributed to the limited number of available stable precursors. Since amine radical cations offer increased reactivity and selectivity in chemical transformations compared with neutral aminyl radicals, their generation is of utmost importance. Recently, a surge of reports has been revealed using visible light photoredox catalysis. It has been demonstrated that amines can act as an electron donor in a reductive ...

A base-promoted domino reaction to synthesize the 2,3-disubstituted indoles from 2-aminobenzaldehyde/2-amino aryl ketones, tosylhydrazine, and aromatic aldehydes has been developed. This strategy provides a simple and beneficial way for the construction of 2,3-disubstituted indole compounds from readily available starting materials under mild conditions.

A series of chiral amino alcohol ligands was prepared using commercial amino alcohols and phthalaldehydes. These ligands were used as catalysts in asymmetric Henry reactions in the presence of Cu(II) ions giving good yields (up to 97%) and enantiomeric excesses (ee, up to 98%). The DFT calculations showed the effect of the trans / cis configurations of the Cu-complexes on the origin of enantioselectivity. The easy catalyst preparation, mild reaction conditions, high yields and excellent enantioselectivities make these catalysts suitable for widespread use.

Air-stable and tunable chiral bisdihydrobenzooxaphosphole ligands (BIBOPs) were employed in rhodium-catalyzed asymmetric hydroformylation of various terminal olefins with excellent conversions (>99%), moderate-to-excellent enantioselectivities (up to 95:5 er), and branched to linear ratios (b:l) of up to 400.

A cobalt-promoted coupling reaction of triethoxysilanes, sulfur dioxide, and electrophiles is developed. Benzylic, allylic or alkyl bromides are all efficient as electrophiles in this transformation. Moreover, the reactions with other electrophilic partners including iodonium salts and electron-poor (hetero)aryl chlorides proceed smoothly as well under the standard conditions. The sulfinate intermediates are generated in situ from the reaction of triethoxysilanes and sulfur dioxide under cobalt-promoted conditions, which subsequently combine with various electrophiles to produce the corresponding sulfones in moderate to good yields.

The coupling of multi-step reactions catalyzed by a heterogeneous catalyst is an important path to accomplish some unconventional chemical transformations. Since the starting materials generated from previous steps were adsorbed on the catalyst, the activation energy of following steps was largely decreased, and thus the reaction conditions were more mild and environmental friendly. Catalyzed by a multifunctional Cu–Pd/γ-Al2O3 catalyst, the transfer hydrogenation and successive cyclization coupling reaction from o-nitroaniline and alcohol to afford benzimidazole derivatives in high yield was realized. The catalyst could be reused several times without loss of activity. The synergies of reforming hydrogenation of Cu–Pd bimetal and support acidity of γ-Al2O3 were responsible for this catalytic transformation.

Carbon nano-onions (CNOs) are one of the most promising anode materials for lithium ion batteries (LIBs) because of their outstanding physicochemical properties. In this review, large-scale preparation methods of CNOs, including both traditional and some newly developed approaches in recent years, are summarized. For three of the most important methods of synthesis, arc discharge in water, chemical vapor deposition and nanodiamond annealing in vacuum/inert gases, the effect of process parameters on the synthesis of CNOs is systematically reviewed. The characteristics of emerging methods for fabricating CNOs are also assessed briefly. Afterwards, functionalization including physical/chemical activation and heteroatom-doping, which plays an import role in determining the performance of CNO anodes by altering specific surface area, degree of graphitization, and pore volume distribution of CNOs, are thoroughly reviewed based on analysis of the literature. Finally, the recent progress of CNOs and CNO-based hybrid materials utilized as anodes for LIBs are reviewed and the future direction of research for fabricating high performance CNOs and CNO-based hybrid anodes for LIBs is proposed.

Pd-catalyzed regioselective coupling of γ-C(sp3)–H bonds of oxalyl amide-protected amino acids with heteroaryl and aryl iodides is reported. A wide variety of iodides are tolerated, giving the corresponding products in moderate to good yields. Various oxalyl amide-protected amino acids were compatible in this C–H transformation, thus representing a practical method for constructing non-natural amino acid derivatives.

A CuTC-promoted C–N cross-coupling of 1,2-di(pyrimidin-2-yl) disulfides with N-heterocyclic compounds including indoles, triazole benzotriazole, and benzoimidazole by C–S cleavage of the disulfides is reported.

The title reaction under conditions A) leads to formation of a series of chlorinated spiro[benzofuran-2,5′-oxazole]s with 2 contiguous stereocenters.

A Palladium-catalyzed α-arylation of sulfonamides with aryl chlorides is presented. A Buchwald type precatalyst formed with Kwong's indole-based ligand enabled this transformation to be compatible with a large variety of methyl sulfonamides and aryl chlorides in good to excellent yields. Importantly, under the optimized reaction conditions, only mono-arylated products were observed. This method has been applied to the efficient synthesis of sumatriptan, which is used to treat migraines.

MicroRNAs (miRNAs), which are characterized by highly conserved and small non-coding RNAs, have been a hot spot regarding biological processes such as cellular proliferation, apoptosis and metabolism as well as cellular differentiation, signal transduction and carcinogenesis. MiRNA-106a (miR-106a), a member of the miR-17 family, has been validated to be aberrantly regulated in the diversity of tumors. The purpose of this review is supposed to deliver an intricate overview of miR-106a, including its role in cell proliferation, apoptosis, cell cycle, invasion and metastasis, involvement in drug resistance as well as its interactions with the target proteins and signaling pathways involved.

A highly regio- and stereoselective Rh-catalyzed intermolecular head-to-head [2 + 2] cycloaddition of allenamides was developed. The intermolecular cycloadducts, trans-dimethylenecyclobutane-1,2-diamine derivatives, were achieved in good yields with high regioselectivity and stereoselectivity.

Pale yellow crystals of the title compounds are prepared from mixtures of M(OAc)2 (M: Zn, Cd), KOH, Sb2S3, and thiourea as reactive flux (autoclave, 473 K, 4 d, 47% and 78% yield for the Zn and Cd compound, respectively).