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An efficient synthesis of functionalized γ-lactones has been developed involving Sakurai exo-cyclization/rearrangement of 3,3-bis(silyl) enol esters with a tethered acetal. While the steric and electronic effects of geminal bis(silane) favor the desired Sakurai pathway, the methoxy species formed in the deprotection step also facilitates both cyclization and rearrangement. The synthetic value of this approach has been demonstrated by efficiently transforming the E-vinylsilane into enyne and the γ-lactone moiety into multisubstituted THF.

A novel visible-light-promoted copper-catalysed process for the Csp–Csp cross-coupling reaction of terminal alkynes at room temperature is described. The current photochemical method is simple, highly functional group compatible, and more viable towards the construction of bio-active 1,3-unsymmetrical conjugated diynes without the need of bases/ligands, additives and expensive palladium/gold catalysts.

A Pd(II)-catalyzed enantioselective C–H cross-coupling of benzylamines via kinetic resolution has been achieved using chiral mono-N-protected α-amino-O-methylhydroxamic acid (MPAHA) ligands. Both chiral benzylamines and ortho-arylated benzylamines are obtained in high enantiomeric purity. The use of a readily removable nosyl (Ns) protected amino group as the directing group is a crucial practical advantage. Moreover, the ortho-arylated benzylamine products could be further transformed into chiral 6-substituted 5,6-dihydrophenanthridines as important structural motifs in natural products and bioactive molecules.

Porous amorphous Si is prepared by solvothermal treatment of a solution of SiCl4 in anhydrous glyme to which Mg powder is added (autoclave, 100 °C, 10 d).

An aldehyde-selective Wacker-type oxidation of allylic fluorides proceeds with a nitrite catalyst.

Two new N -methyladenine-containing diterpenes, nemoechines F ( 1 ) and G ( 2 ), were isolated from the South China Sea sponge Agelas aff. nemoechinata . The structures were assigned on the basis of spectroscopic date. Compound 2 showed weak activity against Jurkat cell lines with IC 50 of 17.1 μmol/L.

A practical and efficient method for the preparation of 1,5-benzothiazepinone derivatives in good yields has been developed using tetrabutylammonium fluoride (TBAF) as a catalyst. This study not only expands the previous work on the substrate scope and also provides more understanding of the chemistry of such drug scaffolds.

For the first time, the use of metal catalyst NiBr2·diglyme for the title reaction is described to yield a wide range of silylated compounds.

The electrochemical reaction of dicarbonyl compounds (I) and (VII) with ammonium carbamodithioate (II) as a sole amino and thiocyanate source gives rise to (E)-adducts (III) and (VIII), respectively.

An efficient protocol for the synthesis of sulfonamides via the electrochemical oxidative amination of sodium sulfinates has been developed. The chemistry proceeds in a simple undivided cell employing a substoichiometric amount of NH4I that serves both as a redox catalyst and a supporting electrolyte; in this manner additional conducting salt is not required. A wide range of substrates, including aliphatic or aromatic secondary and primary amines, as well as aqueous ammonia, proved to be compatible with the protocol. Scale-up was possible, thereby demonstrating the practicality of the approach. The electrolytic process avoids the utilization of external oxidants or corrosive molecular iodine and therefore represents an environmentally benign means by which to achieve the transformation.

Efficient electrochemical amino-oxygenation of styrenes has been developed for the synthesis of 3-methoxyindolines and 3-ethoxyindoline, using a simple beaker-type undivided cell with n-Bu4NI serving as a redox catalyst under constant current electrolysis (CCE) conditions. The chemistry proceeds in a paired electrolysis mode, avoiding the utilization of external oxidants and bases and therefore represents an environmentally benign means. The process also works in the absence of an additional conducting salt. Gram-scale reaction further demonstrates the practicability of the protocol. Proton NMR spectroscopy was used to demonstrate that the amino-oxygenation of N-(2-vinylphenyl)sulfonamides likely involves the initial iodoamination of the alkene, followed by nucleophilic substitution of the methoxide/ethoxide generated at the cathode.

A novel DBU-mediated stereoselective spirocyclopropanation of para-quinone methides with sulfonium salts has been developed on the basis of the mode involving a 1,6-conjugate addition/intramolecular dearomatizing cyclization cascade. This reaction provides a mild and effective method for the assembly of synthetically and structurally interesting spirocyclopropanyl para-dienones. The feasibility for the enantioselective access to such functionalized para-dienones has also been explored by using the axially chiral sulfonium salt. Importantly, the regioselective ring openings of the related spirocyclopropanyl para-dienones have been achieved divergently.

An efficient synthesis of indazoles from readily accessible E/Z mixtures of o-haloaryl N-to-sylhydrazones has been developed. The thermo-induced isomerization of N-tosylhydrazones is discussed. A series of valuable indazole derivatives are prepared in good yields, and the method has been successfully applied to the synthesis of the bioactive compounds, lonidamine, AF-2785, axitinib, YC-1 and YD-3.

A total synthesis method for protosappanin A, which is a complex natural product with many biological activities, was developed with 6 linear steps. Dibenzo[b,d]oxepinones as the key intermediates of the synthetic route were prepared by a palladium-catalyzed ortho C-H activation/C-C cyclization under microwave irradiation. 25 derivatives of protosappanin A were obtained.

A mild, practical and efficient palladium-catalyzed decarboxylative ortho-aroylation of N-acetyl-1,2,3,4-tetrahydroquinolines with α-oxoarylacetic acids via C–H bond activation is described. This protocol provides efficient access to a series of C8-aroyl terahydroquinolines.

Significant progress has been made in the past decade regarding the development of enantioselective C-H activation reactions by desymmetrization. However, the requirement for the presence of two chemically identical prochiral C-H bonds represents an inherent limitation in scope. Reported is the first example of kinetic resolution by a palladium(II)-catalyzed enantioselective C-H activation and C-C bond formation, thus significantly expanding the scope of enantioselective C-H activation reactions.

Fluorinated derivatives of radicamine A and radicamine B have been synthesized from D-arabinose-derived cyclic nitrone. Structure–activity relationship studies showed that glycosidase inhibition of these fluorinated derivatives was significantly influenced by the position of the fluorine atom. C-7 or C-11 fluorination of the aromatic ring decreased α-glucosidase inhibition of the derivatives, whereas C-8 or C-10 fluorination preserved glycosidase inhibitory activities.

A palladium-catalyzed tandem C–Br/C–H functionalization and cyclization of alkenes with organohalides is reported. This reaction provides an operationally simple method for the synthesis of various fluorene, pyrroloindole, and benzoxazine derivatives, which are useful pharmaceutical framework and photoelectronic devices. Two new C–C/O bonds, a quaternary carbon center and a new ring, are simultaneously formed in this one-pot reaction.

The generated reactive intermediate is trapped with methanol, ethanol or primary amines, thus providing the corresponding aza-spirooxindole sulfonates or sulphonamides, respectively.

A Cu-mediated/catalyzed selective oxidative dual C–H bond cleavage of an arene and alkylnitrile or acetone is reported. This method provides a novel approach to highly functionalized fluorene and pyrroloindole derivatives, which are useful in pharmaceutical and photoelectronic areas. In this reaction, two new C(sp3)–C(sp3) and C(Ar)–C(sp3) bonds, a quaternary center and a five-membered ring are simultaneously formed.

The development of highly-efficient, stable and cost-effective electrocatalysts for the oxygen evolution reaction (OER) is critical for a range of renewable-energy technologies, including metal–air batteries, fuel cells and water-splitting reactions. However, most of the well-developed electrocatalysts are semiconductors or insulators with poor conductivity, which has profoundly inhibited their overall OER efficiency. In this study, metallic cobalt nitrides (Co2N, Co3N and Co4N) arising from electron delocalization modulation have been investigated for OER electrocatalysts in alkaline solution for the first time. Benefiting from the synergistical engineering of the electrical conductivity and nitrogen content, the simple metallic Co4N catalyst without modifications exhibits a stable current density of 10 mA cm−2 at a small overpotential of 330 mV for OER with a Tafel slope as low as 58 mV dec−1 in alkaline medium, which is superior to most of the unmodified metal oxide electrocatalysts reported to date. Our finding introduces new possibilities for the design of highly active electrocatalysts using synergistical electrical conductivity regulation and composition modulation.

Armed thioglycosides can be activated with aryl(trifluoroethyl)iodonium triflimide in 2:1 CH2Cl2/pivalonitrile or a solvent combination of CH2Cl2, acetonitrile, isobutyronitrile, and pivalonitrile (6:1:1:1) at 0 °C for glycosylation reactions that proceed in good yield and moderate to excellent selectivity (up to 25:1 β/α). Comparison to other common glycosylation promoters reveals that both the mixed solvent and the iodonium salt promoter are required for stereoselectivity.

The first successful example of a visible-light-induced copper-catalyzed process for C-H annulation of arylamines with terminal alkynes and benzoquinone is described. This three-component reaction allows use of a variety of commercial terminal alkynes as coupling partners for the one-step regioselective synthesis of functionalized indoles. Moreover, the current process represents a sustainable and atom-economical approach for the preparation of complex indoles from easily accessible starting materials under visible-light irradiation, without the need for expensive metals and harsh reaction conditions.

The title reaction affords optically active isatin-derived N,O-aminals (III) and (V) in good yields and with up to 92% e.e..

Unprecedented bridged bicyclic amidines are obtained through a highly stereoselective ketenimine formation/cyclization/aza-Cope rearrangement cascade.

Two new metal chalcoiodides were synthesized by solid-state reactions at 400 °C. Crystal Data: Bi2CuSe3I, 1, monoclinic, C2/m, a=14.243(2) A, b=4.1937(7) A, c=14.647(2) A, β=116.095(2)°, V=785.7(2) A3, and Z=4; Bi6Cu3S10I, 2, orthorhombic, Pnma, a=17.476(2) A, b=4.0078(4) A, c=27.391(2) A, V=1918.5(3) A3, and Z=4. Compound 1 adopts a three-dimensional structure formed by two alternative layers, which consist of BiSe5 square pyramids, BiSe4I2 octahedra, CuSe4 tetrahedra, and CuSe2I2 tetrahedra. Compound 2 possesses a new open framework built up of BiS5 square pyramides, BiS6 octahedra, BiS8 polyhedra, and CuS4 tetrahedra where I− anions are uniquely trapped within the tunnels. Both electronic structures reveal that bismuth and chalcogenide orbitals dominate the bandgaps. The Cu d and I p states contribute to the top of valence bands, in which the distribution of I orbitals may correspond to the relative bonding interactions in 1 and 2. The optical bandgaps determined by the diffuse reflectance spectra are 0.68 eV and 0.72 eV for 1 and 2, respectively. 1 is a p-type semiconductor with high Seebeck coefficients of 460–575 μV/K in the temperature range of 300–425 K. The electrical conductivity is 0.02 S/cm at 425 K for the undoped sample. The thermal conductivity is 0.22 W/mK at 425 K.

A novel copper-catalyzed regiodivergent alkylboration of alkenes with bis(pinacolato)diboron and alkyl halides has been developed. The regioselectivity of the alkylboration was controlled by subtle differences in the ligand structure. The reaction thus enables the practical, regiodivergent synthesis of two different alkyl boronic esters with complex structures from a single alkene.

A geminal bis(silane)-controlled regio- and stereoselective oxidative Heck reaction of enol ethers with terminal alkenes has been developed. The reaction proceeds with α,β-coupling regioselectivity to give push–pull Z,E-1,3-dienes in good yields. The product showed valuable utility in Sakurai homoallylation with acetals to generate α-substituted-γ-keto esters with good anti-selectivity.

An effective Friedel-Crafts alkylation reaction of electron-rich aromatics with N-vinylamides, induced by electrochemically in situ-generated TBPA radical cation, has been developed; the resulting adducts are produced in good to excellent yields. In the "ex-cell" type electrolysis, TBPA is transformed to its oxidized form in situ and subsequently employed as an electron transfer reagent to initiate a cationic chain reaction. An easily recoverable and reusable polymeric ionic liquid-carbon black (PIL-CB) composite was also utilized as a supporting electrolyte for the electrochemical generation of TBPA cation radical, without sacrificing efficiency or stability after four electrolyses. Cyclic voltammetry analysis and the results of control experiments demonstrate that the reaction of electron-rich aromatics and N-vinylamides occurs via a cationic chain reaction, which takes place though an oxidative activation of a C-H bond of electron-rich aromatics instead of oxidation of the N-vinylamide as previously assumed.

A copper-mediated oxycyanomethylation reaction of olefinic amides with acetonitrile was developed for the synthesis of important benzoxazine derivatives. The reactions involve the activation of the C(sp3)–H bond of acetonitrile and radical cyclization processes for the construction of new C–C and C–O bonds.

Intramolecular Friedel–Crafts acylation reactions of 2-arylphenoxyacetic acids are accomplished using trifluoroacetic anhydride or trifluoromethanesulfonic acid at 0 °C or room temperature. Depending on the reaction conditions, dibenzoxepines or arylcoumaranones are obtained in good yields and with high selectivities (83–100%). Plausible mechanistic pathways for the selective formation of the different reaction products are discussed.

An acceptor-free catalysis protocol for the deoximation of ketoximes and aldoximes using RuCl3 as the catalyst has been developed. Under the optimized conditions, various oximes were converted to ketones and nitriles with excellent isolated yields.

Ag(I)-mediated conversion of structurally diverse phenols to their CF3-ethers is achieved using CF3-SiMe3 as commercially available CF3-nucleophile.

The concise synthesis of 3-substituted or non-C3-substituted isoquinolines through Rh-catalyzed sequential oxidative C–H activation/annulation with geminal-substituted vinyl acetates was developed with good functional group tolerance. The protocol was successfully applied to the total synthesis of the natural product papaverine.

A new “single-flask” method was developed for the synthesis of imidazolidines and pyrrolidines with high stereoselectivity. First, a Schiff base was arylated with an aryne. Second, an intramolecular proton transfer took place from the methylene position to the anionic aryne ring. Third, the resultant ylide reacted with a second equivalent of the same Schiff base in situ or an electron-deficient alkene through a (3+2) cycloaddition. These sequential tandem 1,2-addition/(3+2) cycloaddition reactions led to the desired heterocycles in 63–88 % yields.

A copper-catalyzed annulation of ethylene glycol with various 1,3-dicarbonyl compounds, including (hetero)arylacetoacetic esters, amides, ketones, and thioesters is elaborated which provides 2,3-disubstituted furans, mostly regioselectively, in moderate to high yields.

Sulfonylation of alcohols (I) provides allylic sulfones, which undergo an oxidative functionalization to yield ketosulfones (IV) and (X) or triflyl allylic alcohols (VII).

2,3-Dimethylimidazole-1-sulfonyl azide triflate reacts with 3-substituted indoles to deliver 2-iminoindolines, 2-aminoindoles, or 2-imino-3-aminoindolines by using different conditions. This imidazolium sulfonyl azide shows higher reactivity toward carbon nucleophile indoles than ordinary alkyl/aryl sulfonyl azides.

Four new lignans [epihenricine B (I), methylmachilusol D (IIa, III), and isofragransol A (IIb)] along with 23 known compounds are isolated from title roots.

Black phosphorus quantum dots (BPQDs) were synthesized using a liquid exfoliation method that combined probe sonication and bath sonication. With a lateral size of approximately 2.6 nm and a thickness of about 1.5 nm, the ultrasmall BPQDs exhibited an excellent NIR photothermal performance with a large extinction coefficient of 14.8 L g(-1) cm(-1) at 808 nm, a photothermal conversion efficiency of 28.4%, as well as good photostability. After PEG conjugation, the BPQDs showed enhanced stability in physiological medium, and there was no observable toxicity to different types of cells. NIR photoexcitation of the BPQDs in the presence of C6 and MCF7 cancer cells led to significant cell death, suggesting that the nanoparticles have large potential as photothermal agents.

An acid-promoted self-1,3-dipolar cycloaddition of ketimines derived from isatins and benzylamines was successfully developed to assemble unprecedented dispirooxindole–imidazolidine ring systems. Generally, excellent diastereoselectivities (only a single stereoisomer formed) and good yields (up to 94%) were obtained. Consequently, this self-1,3-dipolar cycloaddition protocol offers facile access to a novel dispiroheterocyclic skeleton.

A variety of 2-fluoroallylic amines, ethers, esters, and alkylation products are efficiently obtained with high Z-selectivity through regioselective activation of gem-difluorinated cyclopropanes induced by C—C bond cleavage.

A simple method was developed for the direct fluorination of 5-iodotriazoles with AgF as fluoride source and N1,N1,N2,N2-tetramethylethane-1,2-diamine (TMEDA) as ligand. This method is compatible with various functional groups. 5-Iodotriazoles without aromatic groups at the 4-position or aliphatic substituents at the N1 position can also be smoothly converted to the corresponding 5-fluorotriazoles. Preliminary mechanism studies were also performed.

Two unique carbazole-indole-type dimeric alkaloids, glycosmisines A (1) and B (2), have been isolated from the stems of Glycosmis pentaphylla and their structures are elucidated by 1D and 2D NMR analyses, and their cytotoxicity against the growth of three cancer cell lines (A549, HepG-2 and Huh-7 cells) in culture was investigated using an MTT assay. Compounds 1 and 2 exhibited significant levels of cytotoxicity against three human cancer cell lines, and these two compounds also induced apoptosis in the same cell lines, as evidenced by changes in the morphological features of cells treated with these compounds and their dose-dependent accumulation of a sub-G1 population.

The direct decarboxylative arylation of α-oxo acids has been achieved by synergistic visible-light-mediated photoredox and nickel catalysis. This method offers rapid entry to aryl and alkyl ketone architectures from simple α-oxo acid precursors via an acyl radical intermediate. Significant substrate scope is observed with respect to both the oxo acid and arene coupling partners. This mild decarboxylative arylation can also be utilized to efficiently access medicinal agents, as demonstrated by the rapid synthesis of fenofibrate.