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β-Halohydrins bearing transformable halo- and hydroxyl groups, are easily converted into various valuable blocks in organic and pharmaceutical synthesis. A diastereoselective β-halogenation of benzylic alcohols was achieved under simple and low-cost conditions, which provided a direct synthesis of β-halohydrins. The simple reaction conditions, easily available reagents, high diastereoselectivities, and additional oxidant-free make this reaction very attractive and practical.

The balance of adipogenic and myogenic differentiation of skeletal muscle-derived mesenchymal stem cells is particularly important in muscle development and intramuscular fat deposition. This study aimed to explore the differential regulation between adipogenic and myogenic precursors by comparative analysis of their global proteome expression profile. Adipogenic and myogenic precursors isolated from neonatal porcine longissimus dorsi muscle by the preplate method were verified for their unique and distinct differentiation potential under myogenic or adipogenic induction. A total of 433 differentially expressed proteins (DEP) ( P0.05 and FC1.20 or0.83) between adipogenic and myogenic precursors were detected via a tandem mass tag (TMT)-coupled LC-MS/MS approach, including 339 up-regulated and 94 down-regulated proteins in myogenic precursors compared with adipogenic precursors. On the basis of functional annotation and enrichment analysis of 433 DEP, adipogenic and myogenic precursors showed significantly different metabolic pattern of energy substances and differential regulations of gene expression, cell structure and development, ion homeostasis, and cell motility and migration. Three pathways including PPAR signaling pathway, phosphatidylinositol signaling system, and autophagy signaling pathway, which was differentially regulated between adipogenic and myogenic precursors, was also discovered to play crucial roles in cell differentiation. In conclusion, these differentiated regulation patterns between the two cell subsets of mesenchymal precursors together defines their differentiation potential specificity.

Reliability and security are essential concerns in DC power system. However, due to the limited capacity of DC circuit breaker (DCCB), the rapidly growing fault current cannot be reliably interrupted. Thus the reliability of the DC power system cannot be guaranteed. In this paper, a novel current-limiting circuit based on resistive-type superconducting fault current limiter (R-SFCL) is proposed to restrain fault current. The operation procedure of the proposed current-limiting circuit is presented in detail. Then, a detailed mathematical model of opening process is established to analyse parameter design. Finally, the simulation results verify the effectiveness of this circuit. Compared with the traditional current limiting solutions, the proposal can effectively limit the fault current to achieve a more reliable breaking serious fault, and the reliability of DC system can be improved. Furthermore, overvoltage on DCCB is also prevented so that the arrester can be cancelled.

Summary The cycloaddition reactions have been explored extensively and provided an efficient strategy for the synthesis of cyclic compounds. Traditionally, the reaction partners were in extenso incorporated into the cyclic products without fragmentation. From a different perspective, if certain fragmentations via chemical-bond cleavage are involved in this cycloaddition reaction, it would change the assembly sequence and enable more product diversity. Here, we report a chemoselective nitrosylation of anilines and alkynes through fragmentary or complete NO radical incorporation. The formation of multiple C–N bonds, an unexpected C–N bond, and N=O bond cleavage make this fragmentary cycloaddition reaction an efficient approach to 2,5-dihydrooxazoles, 1 H -1,2,3-triazole 2-oxides or quinoxaline N -oxides. Facile operation in open-air, metal-free, and mild conditions renders this protocol particularly practical and attractive. A series of mechanistic studies and density functional theory calculations were also conducted, which help to explain the fragmentary or complete NO incorporation processes, broadening the field of new reaction discovery.

A novel and efficient oxygenation approach to trisubstituted oxazoles via a copper-catalyzed aerobic oxidative dehydrogenative annulation of amines, alkynes, and O2 has been developed. This transformation combines dioxygen activation and oxidative C–H bond functionalization and provides a practical protocol for the preparation of oxazole derivatives, which are privileged units found in various bioactive compounds or other natural products. 18O-labeling experiments were conducted to reveal that oxygenation was involved in this chemistry.

A novel and practical Cu-catalyzed aerobic oxidative synthesis of thiazoles was developed. This chemistry for the first time achieved thiazole construction from simple aldehydes, amines, and element sulfur through multiple Csp3–H bond cleavage processes. Molecular oxygen was used as a green oxidant in this oxidative protocol. The substrate scope is broad with the tolerance of aliphatic amines. The mechanistic study might promote the reaction design for a new sulfuration/annulation reaction with readily available element sulfur.

Oxygenases-catalyzed reductive activation of molecular oxygen and incorporation of O atoms into an organic molecule is undoubtedly one of the most attractive research areas. Typically, these oxygenation reactions proceed with high selectivity and reactivity, which is seldom found in its "biomimetic" chemocatalytic counterparts. Furthermore, enzymatic oxygenation can avoid undesired overoxidation, which is frequently observed in (industrial) chemical transformation. Therefore, it is not surprising that tremendous attention has been paid to enzymatic oxygenation. Their application in organic synthesis has been steadily growing over the years. The goal of the present Review is to provide a handy reference for chemists interested in using homogeneous oxygenase catalysis and those interested in discovering new types of biomimetic oxidations and oxygenations with dioxygen. In this Review, we will review the recent advances in in homogeneous oxygenase catalysis to reveal the great achievements and potentials in this field.

Hydroxyfluoroalkylation of simple alkenes is presented with readily available fluoroalkyl iodides by the virtue of photoredox catalysis in good efficiency and regioselectivity. This chemistry features mild condition, simple operation and good substrate scope. A variety of styrenes as well as non-activated aliphatic alkenes can be selectively transformed to β-fluoroalkylated alcohols. Preliminary mechanistic studies indicated a radical process with fluoroalkyl radicals which were generated from reductive quenching of photocatalytic circle.

An efficient ultra high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry method was developed for separation and profiling of phytochemical constituents of Chinese wild mandarin Mangshanju (Citrus reticulata Blanco). All constituents were well separated within 16 min. Based on retention times, accurate mass, MSE fragments, and/or reference standards as well as databases, a total of 81 compounds were unambiguously identified or tentatively assigned including flavonoid glycosides, acylated flavonoid glycosides, flavones, polymethoxylated flavonoids, and limonoids as well as four other compounds. Among them, 22 polymethoxylated flavones and ten polymethoxylated flavanones/chalcones were identified in Mangshanju, more types than other citrus reported before. A basic procedure for identifying flavonoid-O-glycosides and the aglycones including polymethoxylated flavonoids was proposed. In addition, this method was successfully used to analyze another four mandarin germplasms, Cenxi suan ju, Xipi gousi gan, Nanfeng miju, and Or, showing that Mangshanju contained two characteristic compounds distinct from the other four citrus species. This study systematically profiled phytochemical constituents of Mangshanju, which was helpful for further utilization of Mangshanju owing to its abundant bioactive compounds.

Transition‐metal catalyzed C—H functionalization of benzaldehydes is of great interest in organic synthesis. Herein, we developed a transient directing group assisted amidation of benzaldehydes catalyzed by rhodium catalyst. With the employment of 10 mol% of 4‐trifluoromethyl aniline, the in situ generated imine groups as the directing group efficiently enable this transformation. By using this protocol, a wide range of benzaldehydes were efficiently converted into the corresponding N ‐(2‐formylphenyl)benzamides utilizing dioxazolones as the nitrogen source.

Background Pork produced by outdoor-reared pigs raised mostly on alfalfa pastures attracts increasing population of consumer from most of the world. In China, pigs were raised with alfalfa-containing diets to seek for good quality pork. However, the influence of dietary alfalfa involving high level of insoluble dietary fiber (IDF) on pig intestinal luminal microbiota composition remains unclear. The objective of this study was to investigate the effects of alfalfa on luminal microbiota and short chain fatty acids (SCFA) production, and gene expressions involved in SCFA sensing, transporting and absorbing in pig caecal mucosa. Results Twenty-four growing pigs were randomly allotted to four diets containing 0%, 5%, 10% and 15% alfalfa meal for a 28-d experiment. Ingestion of alfalfa meal-contained diets significantly increased the ratio of body weight gain to feed consumption. Illumina MiSeq sequencing of the V3 region of the 16S rRNA genes showed that alfalfa-containing diet significantly decreased the relative abundance of genera Turicibacter, Acidiphilium, Paracoccus, Propionibacterium, Corynebacterium, Pseudomonas, Acinetobacter, and Staphylococcus, and increased the relative abundance of genera Lachnospira, Marvinbryantia, and Desulfovibrio in the caecal digesta. Butyrate concentration was significantly increased in the hindgut by the supplementation of alfalfa meal in diets. The mRNA gene expressions of FFAR3, SMCT1, MCT1, PYY, and GCG were significantly increased in the caecal mucosa of pigs fed alfalfa meal. Conclusions Our results suggested that alfalfa-containing diet has exerted significant impacts on caecal microbiota composition, butyrate concentration and significantly upregulated mRNA expression of host caecal mucosal genes involved in SCFA sensing and absorption as well as regulation of satiety. Electronic supplementary material The online version of this article (10.1186/s40104-017-0216-y) contains supplementary material, which is available to authorized users.

This study explored and investigated how zearalenone (ZEA) affects the morphology of small intestine and the distribution and expression of ghrelin and proliferating cell nuclear antigen (PCNA) in the small intestine of weaned gilts. A total of 20 weaned gilts (42-day-old, D × L × Y, weighing 12.84 ± 0.26 kg) were divided into the control and ZEA groups (ZEA at 1.04 mg/kg in diet) in a 35-d study. Histological observations of the small intestines revealed that villus injuries of the duodenum, jejunum and ileum, such as atrophy, retardation and branching dysfunction, were observed in the ZEA treatment. The villi branch of the ileum in the ZEA group was obviously decreased compared to that of the ileum, jejunum and duodenum, and the number of lymphoid nodules of the ileum was increased. Additionally, the effect of ZEA (1.04 mg/kg) was decreased by the immunoreactivity and distribution of ghrelin and PCNA in the duodenal and jejunal mucosal epithelial cells. Interestingly, ZEA increased the immunoreactivity of ghrelin in the ileal mucosal epithelial cells and decreased the immunoreactivity expression of PCNA in the gland epithelium of the small intestine. In conclusion, ZEA (1.04 mg/kg) had adverse effects on the development and the absorptive capacity of the villi of the intestines, yet, the small intestine could resist or ameliorate the adverse effects of ZEA by changing the autocrine of ghrelin in intestinal epithelial cells.

Hybrid Polyvinylidene fluoride/Octaphenyl-Polyhedral oligomeric silsesquioxane (PVDF/Octaphenyl-POSS) Lithium-ion battery separator (HPPS) was fabricated and characterized in this paper. HPPS membranes showed good compatibility of membrane matrix due to the organic-inorganic feature of OPS and OPS distributed in membranes very uniformly. Membranes with OPS also displayed commendable thermal stability, it showed nearly zero dimensional shrinkage after hot treatment. The mechanical property (12.7 MPa) of hybrid separators got strengthened after the addition of OPS nano particles which can satisfy the assembling and transportation of cells. Most reliable, separators showed an ionic conductivity of 4.2 × 10 − 3 S/cm and the electrochemical window of 5.6 V. The first discharge capacity of battery with HPPS membrane reached 145.8 mAh/g and the discharge capacity retention was 81.5% from 0.1C to 2C. The HPPS separator was regarded as a promising candidate for the application in Li-ion battery.

Transition-metal catalyzed oxidation reactions are central components of organic chemistry. On behalf of green and sustainable chemistry, molecular oxygen (O2) has been considered as an ideal oxidant due to its natural, inexpensive, and environmentally friendly characters, and therefore offers attractive academic and industrial prospects. In recent years, some powerful organic oxidation methods have been continuously developed. Among them, the use of molecular oxygen (O2) as a green and sustainable oxidant has attracted considerable attentions. However, the development of new transition metal-catalyzed protocols using O2 as an ideal oxidant is highly desirable but very challenging because of the low standard electrode potential of O2 to reoxidize the transition-metal catalysts. In this Account, we highlight some of our progress toward the use of transition-metal catalyzed aerobic oxidation reactions. Through the carefully selection of ligand and the acidic additives, we have successfully realized the reoxidation of Cu, Pd, Mn, Fe, Ru, Rh, and bimetallic catalysts under O2 or air atmosphere (1 atm) for the oxidative coupling, oxygenation reactions, oxidative C–H/C-C bond cleavage, oxidative annulation, and olefins difunctionalization reactions. Most of the reactions can tolerate a range of functional groups. These methods provide new strategies for the green synthesis of alkynes, (α-keto)amides/esters, ketones/diones, O/N-heterocycles, β-azido alcohols, and nitriles. The high efficiency, low-cost, and simple operation under air make these methodologies very attractive and practical. We will also discuss the mechanisms of these reactions which might be useful to promote the new type of aerobic oxidative reaction design.

The selective oxidation of organic molecules is a fundamentally important component of modern synthetic chemistry. In the past decades, direct oxidative C-H and C-C bond functionalization has proved to be one of the most efficient and straightforward methods to synthesize complex products from simple and readily available starting materials. Among these oxidative processes, the use of molecular oxygen as a green and sustainable oxidant has attracted considerable attention because of its highly atom-economical, abundant, and environmentally friendly characteristics. The development of new protocols using molecular oxygen as an ideal oxidant is highly desirable in oxidation chemistry. More importantly, the oxygenation reaction of simple molecules using molecular oxygen as the oxygen source offers one of the most ideal processes for the construction of O-containing compounds. Aerobic oxidation and oxygenation by enzymes, such as monooxygenase, tyrosinase, and dopamine β-monooxygenase, have been observed in some biological C-H bond hydroxylation processes. Encouraged by these biological transformations, transition-metal- or organocatalyst-catalyzed oxygenation through dioxygen activation has attracted academic and industrial prospects. In this Account, we describe some advances from our group in oxygenation via C-H/C-C bond activation with molecular oxygen as the oxidant and oxygen source for the synthesis of O-containing compounds. Under an atmosphere of O

An efficient KI catalyzed nitrogenation of aldehydes and alcohols for the direct synthesis of carbamoyl azides and ureas via a radical process has been developed. The simple operating procedures, the readily available starting materials including aldehydes, alcohols and amines, as well as the utility of the products all make this strategy very attractive.

A concise and efficient aerobic oxidation and oxygenation approach for the construction of 2-aroylquinolines has been developed through copper-catalyzed annulation of anilines, acetaldehydes, and dioxygen. 2,2,6,6-Tetramethylpiperidine-1-oxyl was employed to direct the selectivity toward the desired 2-aroyl products. Molecular oxygen was used in this transformation as an environmentally benign source of oxygen.

An efficient Cs2 CO3 -catalyzed oxidative coupling of thiols with phosphonates and arenes that uses molecular oxygen as the oxidant is described. These reactions provide not only a novel alkali metal salt catalyzed aerobic oxidation, but also an efficient approach to thiophosphates and sulfenylarenes, which are ubiquitously found in pharmaceuticals and pesticides. The reaction proceeds under simple and mild reaction conditions, tolerates a wide range of functional groups, and is applicable to the late-stage synthesis and modification of bioactive molecules.

Transition-metal-catalyzed oxidative C–H cyclization of anilines has been an attractive and powerful strategy for the efficient construction of N-heterocycles. However, primary and tertiary anilines are rarely employed in this strategy due to the relative instability with strong oxidants or the presence of three C–N bonds. We describe here a novel Rh-catalyzed C–H cyclization of a wide range of anilines with alkynes and CO, using an aerobic oxidative protocol. Particularly, the simple primary anilines and readily prepared tertiary anilines could be easily converted to quinolin-2(1H)-ones, which are high value-added, biologically significant N-heterocycles, via C–N bond cleavage.

To investigate coordination of dietary levels of valine (Val) and isoleucine (Ile) on carcass traits and meat quality in pigs, 72 of 73.8 ± 1.6 kg crossbred barrows were randomly divided into a 2 (0.31% vs. 0.65% standard ileum digestible (SID) Val) × 2 (0.25% vs. 0.53% SID Ile) factorial arrangement. As a result, high dietary valine decreased myosin heavy-chain (MyHC)-I mRNA expression, pH24 h value, bound water amount (T21 peak area ratio), sarcoplasmic protein solubility and water holding capacity (WHC) of meat (P

The impact of secondary metabolites on fruit quality, plant growth and human health has led to an increased demand for analytical methods to characterize and quantify these metabolites in recent years. A versatile, sensitive and rapid method based on UHPLC-QqQ-MS/MS was developed for simultaneous qualitation and quantitation of coumarins, furocoumarins, flavonoids and phenolic acids. The chromatographic elution and multiple reaction monitoring mode transitions were optimized to achieve good separation and accurate quantitation of 47 analytes, including 13 groups of isomers, during a single 13 min chromatographic run. This method was validated with good precision and recoveries, wide linear ranges and low limits of detection and quantitation (0.014–1.50 μg L−1). The validated method was further applied to quantify the analytes in flavedo, albedo and pulp from two pummelo varieties, C. grandis ‘Shatianyu’ and C. grandis ‘Guanximiyu’. This method combines high sensitivity, good selectivity, and short chromatographic run time.

Bisphenol A (BPA) is toxic to the reproductive and nervous system, even carcinogenetic in humans and animals. However, few studies focused on effects of BPA on the intestinal tract. Here, we detected BPA-induced injuries on intestinal mucosa and explored a reliable approach to counteract BPA effects. C57BL/6J mice were gavage BPA or BPA accompanied with ingestion of 4% (w/w) of glutamine for 4-wks. In vitro, IEC-6 cells were treated with 0.4 mmol/L BPA for 6 hours mimicking acute injury and 0.2 mmol/L BPA for 12 hours followed with or without the inclusion of 4 mmol/L glutamine for 12 hours to determine cell renewal, mitochondrial function and ROS-JNK/MAPK pathway upon moderate BPA exposure. As results, BPA exposure caused severe intestinal injury, and disturbed intestinal epithelial cell proliferation and apoptosis, accompanied with mitochondrial malfunction and activated JNK/MAPK pathway as well. Notably, glutathione metabolism was implicated in BPA-induce injury. Glutamine could well rescue cell renewal and mitochondrial function from BPA exposure-induced injuries. In conclusion, we demonstrated impaired effect of BPA exposure on intestinal functions, which could be well counteracted by glutamine partly via restoring mitochondrial function and normalizing ROS-JNK/MAPK pathway. Thereby, we provided a novel application of glutamine to rescue intestinal injury.

The performances of modular multilevel converter (MMC) are impacted by the modulation scheme greatly. The modulation scheme is significant to analyze the harmonic characteristics based on nearest level modulation (NLM). According to typical level-shift PWM (LS-PWM), a scheme based on hybrid frequency carrier modulation is presented to analyze harmonic distribution of NLM in this paper. Then, considering harmonics from the DC side in practical engineering, the harmonic characteristics of the output voltages on the AC side are analyzed based on the method of Fourier series. Harmonic distribution characteristics of AC output voltages based on NLM and the influence of harmonics from DC side on it are obtained. It is verified to be correct through comparing the results of simulation theoretical analysis.

An intermolecular reductive C–C coupling of electrophilic alkyl radicals and alkenes has been developed. Thiols were used as both hydrogen-donating reagents and alkyl radical precursors in the presence of triethyl phosphite and radical initiator. A wide range of alkenes, including styrenes, and aliphatic olefins were well tolerated in this transformation. Mechanistic studies indicated that a phosphite promoted radical desulfurization of thiols to access electrophilic alkyl radicals and a radical chain propagation process may be involved in this transformation.

Sourcing nitrogen from nitromethane Nitromethane is produced in bulk quantities for use as a solvent. Its applications as a reagent have focused mainly on the acidity of the methyl protons en route to modifying the carbon center. Liu et al. now report an alternative protocol that activates the nitrogen center to produce an aminating agent. An in situ reductive reaction with triflic anhydride, formic acid, and acetic acid yields an acetylated hydroxylamine, characterized by mass spectrometry. This nitrogen donor conveniently transforms a variety of ketones and aldehydes into amides. Science , this issue p. 281

The present study was carried out to evaluate the effect of dietary supplementation of Scutellaria baicalensis extracts (SBE) on intestinal health in terms of morphology, barrier integrity and immune responses in weaned piglets challenged with Escherichia coli K88. A total of seventy-two weaned piglets were assigned into two groups to receive a basal diet without including antibiotic additives or the basal diet supplemented 1000 mg SBE/kg diet for 14 d. On day 15, twelve healthy piglets from each group were selected to expose to oral administration of either 10 ml 1 × 109 colony-forming units of E. coli K88 or the vehicle control. After 48 h of E.coli K88 challenge, blood was sampled, and then all piglets were killed humanely for harvesting jejunal and ileal samples. Dietary supplementation of SBE significantly decreased diarrhoea frequency and improved feed conversion ratio (P0·05). SBE supplementation to E.coli K88-challenged piglets improved villous height and villous height/crypt depth (P0·05), recovered the protein expression of occludin and zonula occludens-2 in both the jejunum and ileum (P0·05), and mitigated the increases in plasma IL-1β, TNF-α, IL-6, IgA and IgG (P0·05). Meanwhile, dietary SBE effectively inhibited the stimulation of NF-κB, P38 and TNF-α as well as IL-1β in the small intestine of piglets challenged by E. coli K88 and prevented the activation of NF-κB/P38 signalling pathways (P0·05). Collectively, SBE supplementation can potently attenuate diarrhoea in weaning piglets and decrease inflammatory cytokine expressions through inhibiting the NF-κB and P38 signalling pathways.

The phytochemicals in the peel of six oranges and ten mandarins including seven wild varieties and three cultivars were systematically characterised using UHPLC-Q-TOF-MS, and the correlation analysis was performed between phytochemicals and antioxidant capacity in order to investigate the phytochemical contributors to antioxidant capacity. The gradient elution was completed within 16 min and 92 compounds were undoubtedly or tentatively identified. Furthermore, the antioxidant capacities were determined using ABTS, DPPH and FRAP methods. The number of compounds, their contents and the antioxidant capacities were sequenced in the same order of the wild mandarins cultivated mandarins oranges. The correlation analysis that showed five compounds were significantly correlated with the antioxidant capacity and can act as main contributors to the citrus varieties with high antioxidant capacities. This study is systematic for the metabolites identification of mandarins and oranges and provides valuable information for effective utilisation of citrus peel and their bioactive compounds.

Aerobic epoxidation of tertiary allylic alcohols remains a significant challenge. Reported here is an efficient and highly chemoselective copper-catalyzed epoxidation and semipinacol rearrangement reaction of tertiary allylic alcohols with molecular oxygen. The solvent 1,4-dioxane activates dioxygen, thereby precluding the addition of a sacrificial reductant.

Dead-time is commonly designed to avoid shoot-through phenomenon within each arm in voltage source converter. The presence of dead-time tends to cause a power quality issue. Quantitative analysis for dead-time effects is important to mitigate power quality issue. This paper presents two harmonic quantitative analysis methods for dead-time effects in SPWM inverters. First, the harmonic analysis method based on double Fourier series is modified to adapt any initial phase angle and calculate additional harmonics from dead-time effects. Then, a calculation method for switching angles in sinusoidal pulse width modulation (SPWM) is presented. Based on the obtained switching angles and single Fourier series, a more concise calculation method is proposed to perform quantitative analysis for the impact of dead-time on harmonics. The harmonic model is able to reveal the mechanism of harmonics generation from dead-time. Finally, the inner relationship and essential difference between double- and single-Fourier series are summarized. The simulation and experimental results show that both of the proposed quantitative analysis methods can accurately evaluate the effect of dead-time on harmonics.

Cascaded H-bridge rectifiers have recently been increasing applied due to its lots of advantages. However, the load imbalance of the cascaded H-bridge rectifier will induce the DC-link capacitor voltages to be unbalanced, which will cause the semiconductor device to withstand overvoltage and even cause the dc-link capacitor to breakdown and instability of the converter system. Quantitative assessment the load balancing limits is significant for operating stably and system parameter design. This paper presents the working principle, control and modulation methods of cascaded H-bridge rectifier. Based on power balance and modulation principle, a calculation method of the load balancing limits for two-cell cascaded H-bridge rectifiers is proposed. Simulation results are given to validate the correctness of the proposed calculation method. The results show if the load imbalance exceeds the balance control range, additional current harmonics will be generated in AC side.

A direct approach from organoboronic acids and amines to tertiary amides via Pd-catalyzed aerobic aminocarbonylation has been developed. The presence of O2 significantly promotes the efficiency of this transformation. This method uses commercially available organoboronic acids and cheap CO and O2 (1 atm), which renders amides an easy synthesis with broad substrate scope and high functional group tolerance.

An unexpected metal-free C≡C triple bond cleavage, dioxygen activation, and reassembly into tryptophol derivatives has been developed. This chemistry provides a novel, simple, and efficient approach to highly valuable tryptophol derivatives from simple substrates under mild conditions. The mechanistic studies may promote the discovery of new methodologies through C-C bond cleavage and dioxygen activation.

A novel I2-catalyzed direct conversion of cyclohexanones to substituted catechols under mild and simple conditions has been described. This novel transformation is remarkable with the multiple oxygenation and dehydrogenative aromatization processes enabled just by using DMSO as the solvent, oxidant, and oxygen source. This metal-free and simple system demonstrates a versatile protocol for the synthesis of highly valuable substituted catechols and therefore streamlines the synthesis and modification of biologically important molecules for drug discovery.

Oximes and oxime ethers are privileged building blocks and can be conveniently converted to ketones, amines, hydroxylamines, and nitriles. We describe the catalytic decarboxylation of aliphatic carboxylic acids to oxime ethers. With AgNO3 as the catalyst, valuable oxime ethers bearing various substituents could be easily obtained. The broad substrate scope, easy accessibility of aliphatic carboxylic acids, and mild reaction conditions make this strategy immediately applicable to the synthesis, late-stage functionalization, and modification of biologically active compounds. Experimental studies show the reaction undergoes a radical process.