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The mechanistic details of a reported allylation reaction are investigated by means of Stern–Volmer experiments and nanosecond transient absorption spectroscopy. Both reference substrates, i.e., an allylic chloride and a trifluoroacetamide, are inefficient quenchers but large quenching rate constants are observed upon the addition of Ni(COD)2 and a bisoxazoline ligand. The large quenching rate constants and absence of observable photoproducts are consistent with a mechanism that operates by energy transfer between the excited-state iridium photosensitizer and the nickel complex. [ABSTRACT FROM AUTHOR]

The binary metal organic framework (MOF) is composed of two heterometallic ions bonded to an organic ligand. Compared with monometallic MOFs, bimetallic MOFs have greatly improved in terms of structure, porosity, active site, adsorption, selectivity, and stability, which has attracted wide attention. At present, many effective strategies have been designed for the synthesis of bimetallic MOF-based nanomaterials with specific morphology, structure, and function. The results show that bimetallic MOF-based nanocomposites could achieve multiple synergistic effects, which will greatly improve their research in the fields of adsorption, catalysis, energy storage, sensing, and so on. In this review, the main preparation methods of bimetallic MOFs-based materials are summarized, with emphasis on their applications in adsorption, catalysis, and detection of target pollutants in water environments, and perspectives on the future development of bimetallic MOFs-based nanomaterials in the field of water are presented. [ABSTRACT FROM AUTHOR]

Tar and substantial CH4 and CO2 are contained in gasified fuels, which pose an obstacle to direct chemical synthesis, and this is a predominant challenge for biomass gasification technology. Herein, a packed−bed dielectric barrier discharge (DBD) reactor was built for simultaneous CH4 dry reforming and tar removal with a La−Ni/γ−Al2O3 catalyst. The interaction between CH4 dry reforming and tar removal in plasma catalysis was investigated. The results indicated that plasma catalysis can achieve high−efficiency simultaneous tar removal and CH4 dry reforming, as indicated by the reactants' conversion (14% increase for CCH4 and CCO2 at 450 °C in the presence of tar and a 37% increase for the tar removal rate at 360 °C when CH4 and CO2 were introduced), and the mechanism for mutual promotion of CH4 dry reforming and tar removal was elucidated through catalyst characterization results. In addition, a possible reaction mechanism for tar removal via plasma catalysis was proposed. These findings provide valuable insights for simultaneous upgrading and purification of gases generated by biomass gasification. [ABSTRACT FROM AUTHOR]

Furoic acid (FA), a highly valuable intermediate from furfural, is widely used in the resin, plastic, food, and pharmaceutical industries. Currently, FA synthesis involves the oxidation of furfural by O2, catalyzed by noble metals, but the high-cost and low selectivity limit its industrial-scale production. Gluconobacter oxydans mediated FA bio-production by whole-cell catalysis of furfural presents a promising approach with advantages of high selectivity, safety, and environmentally friendly nature, while the bio-toxicity of furan chemicals always hinders their commercial production. In view of a processing-module assembly strategy, we designed a novel and prospective biotechnology to integrate the whole-cell catalysis step, electrodialysis separation step and crystallization/purification step (CCS–EDS–CPS) to achieve continuous and efficient FA bio-production from bio-toxic furfural by whole-cell catalysis. We found a significant enhancement in bioconversion productivity (>10 g L−1 h−1, 98% yield) and cell-recycling by rapid electrodialysis separation of bio-oxidized FA coupled with continuous feeding of furfural in the CCS, which alleviated the bio-toxicity of furan chemicals. Meanwhile, the highly pure FA end-product was spontaneously crystallized and precipitated at room temperature by the enrichment effect of EDS. Thus, the integrated and coupled method presents an advanced technical strategy using the processing-module assembly of biotechnology, and chemical and electrochemical techniques for the bio-oxidation of alcohols into carboxyl acids. [ABSTRACT FROM AUTHOR]

Highlights • The atomic chemical states of interfacial powders are analyzed by EELS. • The sp3 fractions exhibit an increasing tendency from the outer to inner layers. • The c-BN can be transformed from h-BN directly by the variation of sp3 fractions. • The catalysis of Li 3 BN 2 is analyzed briefly in c-BN synthesis under HPHT. Abstract Cubic boron nitride (c-BN) single crystals were synthesized in Li 3 N-BN system. The variation of sp2:sp3 ratio from boron K-edges in different interfacial layers covering on as-grown c-BN single crystals was investigated by electron energy loss spectroscopy. The sp3 fractions from the outer to the inner layers exhibit an increasing trend, correspondingly, the sp2 fractions decrease gradually. The fractions of sp3-bonded BN from the outer to the inner are 10.36%, 11.55%, and 16.67%, respectively. The main phases in the synthesized interfacial powders are confined as c-BN, h-BN microcrystals. On the basis of our findings, it is concluded that c-BN could be transformed from h-BN directly and the catalysis of Li 3 BN 2 was analyzed briefly. [ABSTRACT FROM AUTHOR]

Highlights • Cobalt-ammonia catalysis can replace copper-ammonia catalysis for gold leaching. • The reaction order and activation energy are obtained for Co-NH 3 -S 2 O 3 2− system. • Au leaching reaction is controlled by the diffusion through a solid layer. • The solid layer mainly includes the sulfur and iron species. • Au elution only needs to perform a one-stage process in Co-NH 3 -S 2 O 3 2− system. Abstract The leaching of gold from a gold concentrate calcine using a novel thiosulfate leaching method that utilizes cobalt-ammonia complex as the oxidant in place of the traditional copper-ammonia catalysis was investigated. The result shows that the thiosulfate consumption can be evidently reduced without the impact on the gold extraction. The leaching kinetics of gold in thiosulfate solution with cobalt-ammonia catalysis has been studied. It was found that the reaction orders with respect to ammonia, cobalt and thiosulfate concentrations are 0.42, 0.20 and 0.34, respectively. The optimal pH value for gold leaching is 10.0, and gold can be effectively extracted at ambient temperature. The apparent activation energy is determined to be 5.68 kJ/mol, and this indicates that the gold leaching in the Co-NH 3 -S 2 O 3 2− system is likely to be controlled by the diffusion of reactants and products through a solid layer. The XPS analysis results strongly support this hypothesis. The apparent activation energies of gold leaching in the thiosulfate-only and Cu-NH 3 -S 2 O 3 2− systems are 30.9 kJ/mol and 8.01 kJ/mol, respectively. It can be concluded that the cobalt-ammonia catalysis for thiosulfate leaching of gold has higher catalytic efficiency than copper-ammonia catalysis. The tests for gold recovery from the pregnant solution of the Co-NH 3 -S 2 O 3 2− system by resin adsorption were implemented, and the results demonstrated that the competitive adsorption of cobalt with gold did not occur owing to the weak affinity of the strong base anion resin for cobalt complex ions. Therefore, the elution of gold on loaded resin only needs to perform a simple one-stage process instead of the complex two-stage elution process for the Cu-NH 3 -S 2 O 3 2− system, which will be contribute to reduce the cost of gold recovery from the pregnant solution. [ABSTRACT FROM AUTHOR]

Natural manganese ore catalysts for selective catalytic reduction (SCR) of NO with NH3at low temperature in the presence and absence of SO2and H2O were systematically investigated. The physical and chemical properties of catalysts were characterized by X-ray diffraction, Brunauer–Emmett–Teller (BET) specific surface area, NH3temperature-programmed desorption (NH3-TPD) and NO-TPD methods. The results showed that natural manganese ore from Qingyang of Anhui Province had a good low-temperature activity and N2selectivity, and it could be a novel catalyst in terms of stability, good efficiency, good reusability and lower cost. The NO conversion exceeded 85% between 150°C and 300°C when the initial NO concentration was 1000 ppm. The activity was suppressed by adding H2O (10%) or SO2(100 or 200 ppm), respectively, and its activity could recover while the SO2supply is cut off. The simultaneous addition of H2O and SO2led to the increase of about 100% in SCR activity than bare addition of SO2. The formation of the amorphous MnOx, high concentration of lattice oxygen and surface-adsorbed oxygen groups and a lot of reducible species as well as adsorption of the reactants brought about excellent SCR performance and exhibited good SO2and H2O resistance. [ABSTRACT FROM PUBLISHER]

A novel method was developed for the construction of biologically active poly-substituted cinnolines from easily accessible hydrazones in good to excellent yields. A simple copper catalyst could efficiently promote C−N bond formation through selective C−H functionalization and dehydrogenative amination. Furthermore, the inert C−Heteroatom (O/F/N) bonds are susceptible to cleavage in high selectivity in the newly developed aerobic annulation, in preference to the alternative C−H bond, which is left intact. [ABSTRACT FROM AUTHOR]

[Display omitted] • Plasma-catalytic steam reforming of tar model compound was carried out. • The synergy of plasma catalysis was evaluated under different conditions. • The highest toluene conversion was 87.1% with a gas yield of 72.6%. • The reaction temperature affected the electric field thus the reaction performance. In this study, steam reforming of toluene was carried out in a dielectric barrier discharge (DBD) plasma reactor combined with Ni/γ-Al 2 O 3 catalysts. The effect of reaction temperature, calcination temperature of catalysts, and relative permittivity of packing materials, on the reaction performance and synergistic effect of plasma catalysis was investigated. The results showed that toluene conversion decreased initially and then increased with increasing temperature, due to a decreasing average reduced electric field and increasing catalytic activity at higher temperatures. At 450 °C, the process achieved a high toluene conversion of 87.1%, a total gas yield of 72.6%, and an energy efficiency of 18.2 g/kWh, demonstrating the potential of this approach for sustainable hydrogen production. Catalysts prepared at lower calcination temperatures or with higher relative permittivity packing materials perform better, owing to the larger Ni surface area available for catalytic reactions and the higher surface discharge facilitating the occurrence of surface reactions. In addition, the synergistic capacity in terms of toluene conversion and gas production exhibited a positive relationship with the metal surface area of catalysts and the relative permittivity of packing materials, while the relationship between reaction temperature and toluene conversion was negative. [ABSTRACT FROM AUTHOR]

Compared with the thiosulfate leaching in the presence of inert quartz, the conclusion was obtained that all studied sulfide minerals including chalcopyrite, galena, sphalerite, pyrite and arsenopyrite could accelerate the thiosulfate consumption and hinder the gold dissolution in varying degree. The dominant cause for these two detrimental effect of sulfide minerals were inferred separately via the analyses of frontier orbital energy and XPS to be the catalysis of these minerals on thiosulfate decomposition and the passivation of gold surface. The passivation layer on gold surface mainly consisted of copper and sulfur species. It was also concluded by leaching tests that HA (sodium humic acid) additive could effectively reduce these harmful effect of sulfide minerals. The acting mechanism of HA during thiosulfate leaching was studied in detail mainly through the analyses of mixed pulp potential, zeta potential and XPS, and was proposed as follows: humic acid radical ions not only weakened the interaction between Cu(II) and thiosulfate via complexing with Cu(II) at axial coordinate sites and relieved the catalytic effect of minerals on thiosulfate decomposition by making the affinity of mineral surfaces for S 2 O 3 2 − disappear, but also prevented passivation species from coating gold surface through electrostatic repulsion. [ABSTRACT FROM AUTHOR]

Thetreatment of 2-(ArNCH)C6H4-HNC9H6N ([NQNANIMe]H, Ar = 2,6-Me2C6H3; [NQNANIEt]H, Ar = 2,6-Et2C6H3; [NQNANIiPr]H, Ar = 2,6-iPr2C6H3) with nBuLi and CrCl3(THF)3achieves the hetero-dinuclearcomplexes [NQNANIR]CrCl(μ-Cl)2Li(THF)2(1a, R = Me; 1b, R = Et; 1c, R = iPr) or bisligated complex κ5-[NQNANIiPr]2CrCl (2c)depending on the reactant ratios used. Reactions of these ligandswith nBuLi and CrCl2(THF)2couldachieve the square-pyramidal complexes [NQNANIR]CrCl(THF) (3b, R = Et; 3c, R = iPr). Complex 3ccan be oxidized by alkyl chloride to dimeric complex {[NQNANIiPr]CrCl}2(μ-Cl)2(4) through a single-electron-transfer mechanism. Similar reactionof 2-(C9H6N)NCHC6H4-HNAr ([NQNINAMe]H, Ar = 2,6-Me2C6H3; [NQNINAEt]H, Ar = 2,6-Et2C6H3; [NQNINAiPr]H, Ar = 2,6-iPr2C6H3) with nBuLi andCrCl3(THF)3furnishes [NQNINAR]CrCl(μ-Cl)2Li(THF)2(5a, R = Me; 5b, R = Et; 5c, R = iPr) in high yields. However,a chromium complex with a butyl-substituted ligand, [NQBuNINAiPr]CrCl2(6), is obtained when 2 equiv of nBuLi is used. The molecularstructures of 1c, 2c, 3c, 4, 5c, and 6are confirmed by X-raycrystallography. Upon activation with MAO, the Cr(III) complexes (1a–1c, 4, and 5a–5c) show moderate catalytic activities (50 to218 kg of PE·mol(Cr)−1·h–1) in ethylene polymerization, whereas the Cr(II) complexes 2c, 3b, and 3care inert under thesame conditions. [ABSTRACT FROM AUTHOR]

Cubic boron nitride (cBN) single crystals are synthesized with lithium nitride (Li3N) as catalyst under high pressure and high temperature. The variation of electronic structures from boron nitride of different layers in coating film on the cBN single crystal has been investigated by X-ray photoelectron spectroscopy. Combining the atomic concentration analysis, it was shown that from the film/cBN crystal interface to the inner, the sp 2 fractions are decreasing, and the sp 3 fractions are increasing in the film at the same time. Moreover, by transmission electron microscopy, a lot of cBN microparticles are found in the interface. For there is no Li 3 N in the film, it is possible that Li 3 N first reacts with hexagonal boron nitride to produce Li 3 BN 2 during cBN crystals synthesis under high pressure and high temperature (HPHT). Boron and nitrogen atoms, required for cBN crystals growth, could come from the direct conversion from hexagonal boron nitride with the catalysis of Li 3 BN 2 under high pressure and high temperature, but not directly from the decomposition of Li 3 BN 2 . [ABSTRACT FROM AUTHOR]

A highly enantioselective NH insertion reaction of α-diazoketones was developed by using cooperative catalysis by dirhodium(II) carboxylates and chiral spiro phosphoric acids. The insertion reaction provides a new access route to diverse chiral α-aminoketones, which are versatile building blocks in organic synthesis, with fast reaction rates, good yields and high enantioselectivity under mild and neutral conditions. [ABSTRACT FROM AUTHOR]

Alkali agents could be used to enhance the extraction of zinc from solution, but excess alkali can lead to emulsification of the solution. In this study, the redox couples of Co(III)/Co(II) could be formed based on the thermodynamic analysis, and catalyze the dissolution of gold in a cobalt–ammonia–thiosulfate system. The catalytic mechanism of cobalt–ammonia for gold dissolution in the thiosulfate solution was further proposed by the analysis of polarization curves to be that NH3 catalyzes the dissolution of gold in the anodic area, and Co(NH3)63+ catalyzes the reduction of dissolved oxygen in the cathodic area. In the dissolution of gold, the concentration of NH3, Co3+ and S2O32− increased, and the dissolution of gold increased. The apparent activation energy for gold dissolution is 41.15 kJ/mol in a temperature range of 25–40 °C, and this demonstrates that gold dissolution is chemically controlled. The SEM-EDS and XPS analyses indicate that the precipitate coating on gold surfaces is mainly S2− in CoS and S8. The decomposition of thiosulfate was also carried out in different thiosulfate solutions. Results have shown that the increase of NH3 concentration can reduce thiosulfate decomposition, while the increase of Co3+ and S2O32− concentration can accelerate thiosulfate decomposition. The apparent activation energy for thiosulfate decomposition with the temperature range of 26.6–41 °C is determined to be 22.12 kJ/mol, which shows that thiosulfate decomposition is mixed chemical-diffusion-controlled. [ABSTRACT FROM AUTHOR]

Over the past two decades, microfluidics, represented by lab-on-a-chip (LoC) systems, have been developed because of their unique advantages of low reactant consumption, environmental friendliness, high safety, high efficiency, high sensitivity, portability, and easy handling of reactants. The distinguishing features of microfluidics have made the on-chip reactor a highly efficient platform for general chemical experiments, especially catalysis. In this paper, through a brief review of the recent work on microfluidic catalysis, we highlight the importance of on-chip catalytic microreactors. New approaches to the fabrication of on-chip catalytic microreactors and their integration with multifunctional components are briefly introduced. Finally, the current challenges and future perspectives of this up-and-coming field are discussed based on our own opinions. It is believed that, with the progress of interdisciplinary cooperation, microfluidics and catalysis could be complementary sciences; catalysts may play a very important role in LoC systems, and on-chip catalytic microreactors could be a highly efficient experimental platform for modern catalysis research. [ABSTRACT FROM AUTHOR]

The article reports on an innovative approach for preparing carbon-doped titania hollow spheres (THS) with hierarchical pore structure by using carbon spheres to play a dual role as both single hard template and the source of carbon doping. It cites other approaches for preparing THS including spray-drying and hydrothermal synthesis. It investigates the crystal structure of THS using x-ray diffraction analysis (XRD). Also shown is the XRD pattern of THS.

Four heterobimetallic lanthanide–potassium complexes stabilized by the carbon-bridged bis(phenolate) ligand MBMP2–(MBMP = 2,2′-methylene bis(6-tert-butyl-4-methylphenolate)), [{(MBMP)2La(THF)2}2K][K(THF)6] (1), [(MBMP)Nd(μ-MBMP)K(THF)]2(2), [(THF)2Sm(MBMP)2K(THF)2] (3), and [(THF)2Yb(MBMP)2K(THF)3] (4), were synthesized, and their structural features were provided. It was found that the ionic radii of lanthanide metals have a profound effect on the structures of the heterobimetallic complexes. Complexes 1to 4are efficient catalysts for amidation reactions of aldehydes with amines to produce amides in good to excellent yields under mild conditions. [ABSTRACT FROM AUTHOR]

Two Schiff base cobalt(II) complexes containing crowned substituents have been synthesized and employed to promote the hydrolysis of p-nitrophenyl picolinate (PNPP) in a buffered micellar solution formed by a cationic Gemini surfactant, bis(hexadecyldimethylammonium)hexane bromide (G(hex)C16, 2Br-) over a pH range of 6.50–8.50. In comparison, the reactivity of PNPP hydrolysis catalyzed by the same catalysts in the other micellar system, formed by a conventional single-chain analogue, that is, hexadecyltrimethylammonium bromide (CTAB), has also been evaluated under a selected condition. The results clearly reveal that the two metallomicelles made of the aforementioned Co(II) complexes and the G(hex)C16 are both efficient for catalyzing PNPP hydrolysis with about 3 orders of magnitude in rate acceleration compared with the background rate of PNPP spontaneous hydrolysis. Moreover, the rates of PNPP hydrolysis catalyzed by the two cobalt(II) complexes in G(hex)C16 micelles are about 2 times higher than in CTAB micelles, correspondingly. In addition, observations show that steric hindrance of substituents of the two complexes is also one of the major influencing factors in the PNPP hydrolytic reaction. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 672–680, 2007 [ABSTRACT FROM AUTHOR]

Abstract: The cleavage of 2-hydroxypropyl p-nitrophenyl phosphate (HPNP) catalyzed by the Zn(II)–biap (biap: -bis(2-ethyl-5-methylimidazole-4-ylmethyl)aminopropane) complex has been investigated spectrophotometrically in a micellar solution of cationic Gemini surfactant 16-2-16 [bis(hexadecyldimethylammonium)ethane bromide] and CTAB (hexadecyltrimethylammonium bromide) at . The experimental results reveal that a higher rate of acceleration (about 2016-fold) of HPNP cleavage promoted by the Zn(II)–biap complex has been observed in the 16-2-16 micellar solution in comparison with the background rate () of HPNP spontaneous cleavage at 25 °C. Reaction rates of HPNP cleavage in CTAB micellar solutions are only about 40% of that in Gemini 16-2-16 micelles under comparable conditions. In addition, the cleavage rates of HPNP in Gemini micelles and in CTAB micelles are respectively 29.5 times and 12 times faster than that in aqueous buffer. Especially, a “sandwich absorptive mode” has been proposed to explain the acceleration of HPNP cleavage in a cationic micellar solution. [Copyright &y& Elsevier]

Abstract: The catalytic activity of Brønsted acid sites in zeolites was studied by the monomolecular conversion of propane over zeolites with varying framework topologies and Si/Al ratios. The rates and apparent activation energies of cracking and dehydrogenation were determined. The activity of the Brønsted acid sites depends on the rate-limiting step of the reaction. In the cracking reaction, the protonation of the alkane is the rate-limiting step, and the heat of reactant adsorption dominates the differences in the observed activity. The similar intrinsic activities over the different zeolites show that the ability of zeolitic Brønsted acid sites to transfer a proton to an alkane does not vary significantly, suggesting that the acid sites that participate in the reaction have very similar strengths. In the dehydrogenation reaction, the rate-limiting step is the desorption of the alkoxide species. The rate is determined by the stability of the alkoxide species, which is influenced by the local geometric and electronic structure of the Brønsted acid site and is affected by zeolite structure and Si/Al ratio. Implications of these conclusions are related to other reactions, such as catalytic cracking and alkylation. [Copyright &y& Elsevier]

Abstract: Scanning Raman spectroscopy, scanning auger microprobe, electron probe microanalysis, X-ray powder diffraction and transmission electron microscopy were used to investigate a thin metal film covering on HPHT as-grown diamond from Fe–Ni–C system. In different regions of the film, the fine structure of carbon and iron atoms are different. It is clear that the microstructure and composition in the inner part of the film near diamond are different from those in other regions of the film. The fine structures of carbon and iron atoms have been greatly transformed. Crystalline graphite and amorphous carbon were not found in the inner part near diamond. The diamond formation should be directly associated with carbide. There exist parallel relationships between the crystal faces of (Fe,Ni) and Fe3C. We suggest that graphite could not be directly catalyzed into diamond structure in the molten film, and the carbon for diamond growth may be related to the decomposition of Fe3C under the effect of (Fe,Ni) phases in the inner part, which can play an important role under diamond growth at high temperature and high pressure. [Copyright &y& Elsevier]

For the first time, a highly enantioselective rhodium-catalyzed arylation of benzoxazinones and quinoxalinones is realized by employing an unsaturated chiral sulfoxide ligand. [ABSTRACT FROM AUTHOR]

There are several limitations of thiosulfate leaching methods in its industrial application. The main limitation is the addition of copper and ammonia which act as catalysts in the thiosulfate leaching process. The introduction of cupric ions can accelerate the rate of gold leaching but cause massive oxidation of thiosulfate, and cupric ions in the leachates are also adverse to gold recovery. Moreover, the presence of ammonia must be taken into account due to the increasing environment concerns. In this paper, a systematic investigation was carried out during oxygen pressure thiosulfate leaching (OPTL) without adding copper and ammonia at elevated temperature and oxygen pressure. Thermodynamic calculations showed that the improvement of temperature and pressure was favorable to gold leaching by thiosulfate. However, high temperature and pressure also caused high thiosulfate consumption (55.3 kg/t-ore of sodium thiosulfate) and relatively low gold extraction (87.6%) without additives. Addition of ammonium alcohol polyvinyl phosphate (AAPP) in the tests could reduce thiosulfate consumption to 45.7 kg/t-ore, whilst 90.2% of gold extraction can be achieved. XPS and SEM studies indicated that AAPP could also hinder the deposition of some passivation species including FeOOH, Fe 2 O 3 , Al 2 O 3 , S0, etc. on the ore surface. The gold recovery from oxygen pressure thiosulfate leach solution was conducted by the method of resin adsorption. Over 98% of gold can be loaded at 1 g/L strong base anion exchange resin of Tulsion A-21S and almost 100% of gold on the loaded resin can be stripped with a two component eluent solution comprising chloride and sulfite. • Gold dissolution during OPTL without additional catalyst is feasible. • The additive AAPP could further increase gold extraction to 90.2%. • Gold can be easily recovered from the pregnant solutions of OPTL by resin adsorption. • The absence of copper and ammonia simplify the composition of solution. [ABSTRACT FROM AUTHOR]

Review: [37 refs. [ABSTRACT FROM AUTHOR]

The title reaction provides a new method for the synthesis of α-diaryl acetates such as (III), (V), and (VII) in good yields and with high enantioselectivities. [ABSTRACT FROM AUTHOR]

Various diarylmethanes are conveniently and efficiently obtained. [ABSTRACT FROM AUTHOR]

An abstract of the article "Copper-Catalyzed Aerobic Decarboxylative Sulfonylation of Cinnamic Acids with Sodium Sulfinates: Stereospecific Synthesis of (E)-Alkenyl Sulfones" by Q. Jiang and colleagues is presented.

This is the first asymmetric N-H insertion of α-diazoketones giving α-aminoketones in good yields and with high enantioselectivities. [ABSTRACT FROM AUTHOR]

Chemical formulas showing highly enantioselective S-H bond insertion cooperatively catalyzed by dirhodium complexes and chiral spiro phosphoric acids are presented.

Review: 103 refs. [ABSTRACT FROM AUTHOR]

Abstract: A facile and environmentally friendly Nafion-H catalyzed multicomponent reaction for synthesis of octahydroquinazolinone derivatives is described. In order to improve the yield and selectivity, the effects of the mole proportion of reactants (cyclic β-diketones, urea and aldehydes) and solvents were investigated. The ability to reuse the catalyst, high yields and easy purification are important features of this process. Interestingly, under similar conditions, the use of nicotinaldehyde and isonicotinaldehyde as the aldehyde component of the reaction gives unexpected products that are distinct from Biginelli products. All of the products were characterized by 1H NMR, 13C NMR, EI-MS and IR, and the structure of one Biglnelli product (4k) was determined by single-crystal X-ray diffraction. [Copyright &y& Elsevier]