State Key Laboratory of Elemental Organic Chemistry

An efficient ruthenium-catalyzed oxidative coupling of indoles and pyrroles with various alkenes at the C2-position assisted by employing the N,N-dimethylcarbamoyl moiety as a directing group is reported. The catalytic reaction proceeds in an excellent regio- and stereoselective manner.

We report herein a new strategy of the Ru-catalyzed intramolecular olefin hydrocarbamoylation for the regiodivergent synthesis of five- and six-membered benzo-fused lactams starting from N-(2-alkenylphenyl)formamides. Using a combined catalyst of Ru3(CO)12/Bu4NI in DMSO/toluene cosolvent (catalytic system A), a 5-exo-type cyclization proceeds favorably to form indolin-2-ones as a major product in good to excellent yield. When the reaction was conducted in the absence of halide additives in DMA/PhCl (catalytic system B), 3,4-dihydroquinolin-2-ones were obtained in major in moderate to high yield via a 6-endo cyclization process. An excellent level of regioselectivity was observed with a variety of substrates to deliver 5-exo- or 6-endo-cyclized lactams. It was found that while the selective cyclization was controlled primarily by the choice of catalytic systems employed, it was also greatly influenced by the structural nature of substrates. A halide-bridged trinuclear complex [Ru3(CO)10(μ2-I)](-) is postulated to be an active species in the catalytic system A. Two reaction pathways are proposed, in which the Ru-catalyzed oxidative addition of formyl C-H or N-H bond initiates the subsequent cyclization processes.

A series of primary-tertiary diamine catalysts were designed and synthesized from primary natural amino acids. Application of these new chiral catalysts in direct aldol reactions of alpha-hydroxyketones showed very good catalytic activity (up to 97% yield) and high syn selectivity (up to syn/ anti = 30:1, 99% ee).

Rh(III)-catalyzed ortho C-H olefination of aryl sulfonamide directed by the SO2NHAc group is reported. This oxidative coupling process is achieved highly efficiently and selectively with a broad substrate scope. The reactions of N-tosylacetamide with acrylate esters afford ortho-alkenylated benzofused five-membered cyclic sulfonamides, whereas styrenes provide the direct diolefination products.

New types of ruthenium catalysts were developed for the chelation-assisted intermolecular olefin hydroesterification that employs 2-pyridylmethyl formate as an ester source. Two classes of ligands, NHCs and phosphines, were found to facilitate the reaction delivering isomeric ester products (linear versus branched) with different ratios, thus allowing access to ligand-guided selective hydroesterification.

Abstract Two pathways that can be used to access ortho ‐olefinated phenol carbamate, including a ruthenium(II)‐catalyzed oxidative olefination of phenol carbamate with acrylates and a rhodium(III)‐catalyzed alkyne hydroarylation of phenol carbamate with internal alkynes through direct C–H activation, are reported. Both reactions afford substituted alkenes in a highly regio‐ and stereoselective manner.

Abstract A concise, efficient and modular route involving Parham‐type cycloacylation as the key step has been used to synthesize six enantiopure phenanthro‐indolizidine alkaloids 1a – c . The preparation of enantiomerically pure tylophora alkaloids and their seco analogues on a large‐scale is now feasible. The alcohol intermediates 8a – c , which are difficult to prepare by other synthetic methodologies, have been synthesized by a metallation–cyclization–reduction sequence in excellent yields.

Owing to the electrocatalytic performance in the nitrate reduction reaction (NO3RR), bimetallic catalysts are emerging reliable candidates for noble metal electrocatalysts to realize the treatment and conversion of nitrate wastewater into valuable ammonia. The bimetallic catalysts can further be economized in the fabrication and enhanced in electrocatalytic performance by using inexpensive biomass-derived mesoporous carbon as supports. Herein, lignin-derived ordered mesoporous carbon (OMC)-supporting bimetallic CuCo nanoparticles (Cu5Co5/OMC) were prepared to enable the nitrate reduction reaction with an ammonia yield rate of 21.05 mg h–1 cm–2, Faradaic efficiency (FENH3) of 96.9% at −0.6 V vs reversible hydrogen electrode (RHE), and a stable FENH3 of above 85% within a wide potential window (−0.2 to −0.8 V vs RHE). An appropriate proportion of copper/cobalt is beneficial to the adsorption and activation of nitrate and progressive hydrogenation through electron redistribution. OMC supports enable uniform dispersion of bimetallic CuCo active sites and good enrichment of reactants. And the density functional theory (DFT) theoretical calculations prove the strong metal–support interaction between CuCo NPs and OMC for boosting the outstanding electrocatalytic performance of Cu5Co5/OMC for NO3RR. The reaction pathway for nitrate reduction was revealed by combination of electrochemical in situ Fourier transform infrared and in situ Raman spectra.

Porous ultrathin carbon-encapsulated FeS₂@C nanooctahedra synthesized by a facile solvothermal and carbon-coating-annealing-pickling strategy exhibit a superior performance for sodium-ion storage.

Abstract Electrocatalytic nitrate reduction (NO3RR) to valued ammonia is an ideal supplementary route to the Haber–Bosch method and a strategy for the removal and utilization of nitrate pollutants. However, due to the fact that NO3RR goes through a complicated multi‐electron/proton transfer, catalysts with monovalent metal sites are difficult to tackle multitasking that it involves, leading to unsatisfactory nitrate conversion efficiency and ammonia selectivity. Herein, heterovalent Fe(OH) 2 /Fe pair sites supported onto carbon nanotubes (Fe(OH) 2 /Fe@CNTs) are presented via electrochemical reconstruction of CNTs‐supporting FeS/Fe 2 C heterostructure. Fe(OH) 2 /Fe@CNTs exhibits a high NH 3 yield rate of 0.67 mmol h −1 cm −2 with a FE of 95.1% at −0.4 V versus RHE, which is mainly attributed to the regulated electronic structure and cooperation of heterovalent iron pair sites. Meanwhile, the adsorption of nitrogen‐containing species is adjusted and the utilization of * H is enhanced. Moreover, a balanced content of Fe(OH) 2 and Fe creates “buffering effect” to maintain its activity and stability. Theoretical calculations combined with in situ FTIR and in situ Raman spectra reveal a novel multiple reaction pathway on heterovalent Fe(OH) 2 /Fe pair sites, entirely different from a single pathway on monovalent Fe or Fe(OH) 2 . Clearly, this study offers a creative strategy for the design of advanced catalysts with multivalent metal sites.

Abstract Fluorinated organic cations are used to enhance the power conversion efficiency (PCE) of quasi‐2D Ruddlesden‐Popper perovskite solar cells (2DRP PSCs), however, most of them focus fluorine substitution on the benzene ring. Herein, a novel α ‐fluorophenylethanimidamide ( α ‐FPEIA) spacer cation with a fluorine atom at α ‐carbon of the amidine group is designed and employed to enhance the performance and stability of 2DRP PSCs. The single‐crystal structure of ( α ‐FPEIA) 2 PbI 4 exhibits stronger interaction between the organic cations and inorganic skeleton, with a larger angle of Pb‐I‐Pb, thus benefiting the charge transfer and improving lattice stability of perovskite film. Furthermore, the theoretical results indicate that ( α ‐FPEIA) 2 PbI 4 exhibits a reduction in the quantum confinement effect, which is conducive to carrier transfer. Additionally, the α ‐FPEIA‐based perovskite film exhibits excellent crystal quality, suitable energy level arrangement, decreased trap states, and extended carrier lifetime. These enhancements boost the PCE of ( α ‐FPEIA) 2 (Cs 0.05 FA 0.8 MA 0.15 ) 4 Pb 5 I 16 ( n = 5) device reaching 18.15% (vs phenethylammonium (PEA)‐based PSCs of 15.38%) along with improving the stability of unencapsulated PSCs. The findings demonstrate that introducing a fluorine atom into the alkyl group of the PEA and replacing the ammonium with the amidine group represents a novel approach for fabricating high‐performance and stable inverted 2DRP PSCs.

Study on relative sensitivity of maize (Zea mays L.) Nongda108 and Nongda3138 to sulfonylurea herbicide chlorsulfuron and tribenuron-methyl using maize taproot length by sand bioassy indicated that, Nongda3138 had higher tolerance to chlorsulfuron and tribenuron-methyl than Nongda108 did. Chlorsulfuron had stronger growth inhibition to maize Nongda108 and Nongda3138 than tribenuron-methyl did. Study on target enzyme of sulfonylurea herbicide acetolactate synthase (ALS) showed that, chlorsulfuron and tribenuron-methyl inhibited ALS in vitro strongly, and non-competitively. In the same concentration of inhibitors, chlorsulfuron had stronger ALS activity inhibition than tribenuron-methyl did. Lower level of chlorsulfuron and tribenuron-methyl has no ALS activity inhibition in vivo, the ALS inhibition only occurred in the condition of high concentration of chlorsulfuron and tribenuron-methyl in vivo.

Six of new N-tert-butyl-N-substitutedbenzoyl-N-(2,4-dimethyl-2,3-dihydrobenzofuran)-7-carbohydrazide derivatives and five of new N-tert-butyl-N-substitutedbenzoyl-N-(5-methylchroman)-8-carbohydrazide derivatives were designed and synthesized from m-cresol. The synthesis highlighted that some kinds of reactions were ameliorated in methodology. An important feature is that 1-(3-allyl-2-hydroxy-4-methylphenyl)ethanone can easily be transformed into 1-(2,3-dihydro-2,4-dimethylbenzofuran-7-yl)ethanone just with concentrated sulfuric acid as catalyst. In addition, we found that 1-(5-methyl-2H-chromen-8-yl)ethanone could not be reduced to 1-(5-methylchroman-8-yl)ethanone directly by hydrogen with Pd/C as catalyst. It is an effective method for protecting 1-(5-methyl-2H-chromen-8-yl)ethanone with ethylene glycol to obtain 5-methyl-8-(2-methyl-1,3-dioxolan-2-yl)-2H-chromene and then reducing by hydrogen with Pd/C as catalyst to produce 1-(5-methylchroman-8-yl)ethanone in one step. Furthermore, SOCl2 can convert 2,3-dihydro-2,4- dimethylbenzofuran-7-carboxylic acid to 2,3-dihydro-2,4-dimethylbenzofuran-7-carbonyl chloride, but it is inefficient for transforming 5-methylchroman-8-carboxylic acid to the corresponding acyl chloride. Hence, different heterocycles on the benzene ring of benzoheterocyle moiety have influence on the reaction property of the corresponding acid. Keywords: Dihydrobenzofuran, chroman, benzoheterocycle, diacylhydrazine, synthesis, insect growth regulator

Branch-connected dimerized acceptors can take full advantages of four end units in enhancing molecular packing comparing to that of terminal-connected ones, thus potentially reaching the best balance between stability and power conversion efficiency (PCE) of organic solar cells (OSCs). Herein, two branch-connected dimerized acceptors, namely D1 and D2, are developed by employing bithiophene and difluorinated bithiophene as linker groups, respectively. Induced by the fluorine atoms on linker group, D2 affords a larger molar extinction coefficient, more importantly, the optimized nanoscale film morphology and superior charge transport behavior comparing to D1. Consequently, D2-based binary OSCs render a good PCE of 16.66%, outperforming that of 15.08% for D1-based ones. This work highlights the great significance of linker group screening in designing high-performance branch-connected dimerized acceptors.

BACKGROUND: Plant diseases caused by viruses and pathogens have posed a serious threat to global agricultural production and are difficult to control. Natural products have always been a valuable source for lead discovery in medicinal and agricultural chemistry. The natural product resveratrol was found to have good antiviral activity against the tobacco mosaic virus (TMV) and fungicidal activities against 14 kinds of phytopathogenic fungi. OBJECTIVE: The aim of this work was to design, synthesize a series of derivatives of resveratrol, and evaluate their antiviral and fungicidal activities systematically. METHODS: Novel resveratrol sulfonate derivatives were prepared by a convenient synthesis method from resveratrol, alkyl sulfonyl chloride, aryl sulfonyl chloride, and heterocyclic sulfonyl chloride. Their structures were also identified by nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry (HRMS). RESULTS: Most of the targets were obtained at a high yield. Compounds I-2, I-5, I-10, II-2, and II-4, with excellent antiviral activities, showed higher anti-TMV activities than those of lead compounds and commercial ribavirin (inhibitory rates of 38, 37, and 38% at 500 μg/mL for inactivation, curative, and protection activities in vivo, respectively). In particular, compounds I-5, I-10, II-2, and II-4 displayed similar inhibitory effects as ningnanmycin (inhibitory rates of 54, 56, and 58% at 500 μg/mL for inactivation, curative, and protection activities in vivo, respectively), the best antiviral agent at present, thereby emerging as new antiviral pilot compounds. Further fungicidal activity tests showed that resveratrol derivatives also displayed broad-spectrum fungicidal activities. CONCLUSION: The anti-TMV activities of these compounds were discovered for the first time. Some of these simply structured compounds showed higher TMV inhibitory effects than ribavirin. The current study provided valuable insights into the antiviral and fungicidal activities of resveratrol derivatives, but more modification of the structure should be conducted.

The title compound, C22H26ClN2O5P, was obtained from the cyclo­addition reaction of 3-(2-chloro­phen­yl)-1-phenyl­nitrilimine (generated in situ) with ethyl E-2-(diethyl­phosphino­yl)acrylate. The pyrazoline ring adopts an envelope conformation. The mol­ecules are linked by a pair of C—H⋯O hydrogen bonds into a centrosymmetric dimer.

The simple, economical and environmentally benign oxidation of sulfides to sulfones and sulfoxides in good yield was achieved by using 30%. aqueous hydrogen peroxide-acetic acid system. Selective oxidation to either the corresponding sulfones or sulfoxides was realized by carefully controlling the reaction temperature. Strongly nonselective sulfide, 4-ethoxycarbonyl-3-methylthio-1H-pyrazole,was converted smoothly to the corresponding sulfoxide and sulfone in excellent yields.

Three kinds of novel N-heterocyclic carbene allyl palladium complexes(Catalyst 1,2 and 3) were synthesized.Norbornene polymerizations were carried out using three catalysts activated with methylaluminoxane(MAO) in toluene.The effects of reaction temperature,the molar ratio of aluminum to palladium and the molar ratio of norbornene to palladium on the catalytic activity and the property of polymer were investigated for catalyst 2.The results show that the catalytic systems display high catalytic efficiency.The highest catalytic efficiency is 3.2×107 g PNE/(mol Pd·h).The resultant polymer is of excellent heat-resistant property.The decomposition is over 400 ℃.According to FT-IR spectra,the polymerization mechanism is vinyl-addition type polymerization.