Recent Advances in Aerobic Oxidative of C-H Bond by Molecular Oxygen Focus on Heterocycles.

Aerobic oxidative cross-coupling represents one of the most straightforward and atom-economic methods for construction of C-C and C-X (X=N, O, S, or P) bonds using air as a sustainable external oxidant. The oxidative coupling of C-H bonds in heterocyclic compounds can effectively increase their molecular complexity by introducing new functional groups through C-H bond activation, or by formation of new heterocyclic structures through cascade construction of two or more sequential chemical bonds. This is very useful as it can increase the potential applications of these structures in natural products, pharmaceuticals, agricultural chemicals, and functional materials.

Efficient Aerobic Oxidative Coupling of Methyl Heteroarenes with Indoles.

Direct oxidative coupling of inert C(sp )-H bond has been a great challenge. Herein, an environmentally friendly aerobic oxidative coupling of α-methyl substituted N-heteroarenes with indoles is reported. A variety of diheteroaryl ketones were prepared in good yields (up to 72 %).

The C(sp)-H bond functionalization of thioethers with styrenes with insight into the mechanism.

A metal-free inactive C(sp)-H bond functionalization of thioethers with styrenes using TBHP as an initiator and DBU as a base has been developed. This transformation has broken through the low activity of thioethers and realized moderate yields. Herein extended experiments were conducted to confirm the radical relay process, reaction energy and intermediate transformations.

Copper-Catalyzed Aldehyde Exchanged Amidation.

The synthesis of bioactive amides has been the pursuit of chemists. Herein secondary amides incorporated with an aldehyde group were first generated using aldehydes and secondary amines. Various (hetero)aryl aldehydes and even aliphatic aldehydes (>40 examples) were converted into the desired products in moderate to excellent yields (up to 89%).

Rare-Earth Y(OTf) Catalyzed Coupling Reaction of Ethers with Azaarenes.

Rare-earth catalysis has become a hot topic in the field of catalytic organic reaction. Chain ethers mostly have lower reactivity and lower boiling points which limited their reaction scope. Herein, we found a rare-earth Y(OTf) can catalyze the coupling reaction of ethers especially chain ethers and thioethers with azaarenes.

New Strategy for Enhancing Energetic Properties by Regulating Trifuroxan Configuration: 3,4-Bis(3-nitrofuroxan-4-yl)furoxan.

It is of current development to construct high-performance energetic compounds by aggregation of energetic groups with dense arrangement. In this study, a hydrogen-free high-density energetic 3,4-bis(3-nitrofuroxan-4-yl)furoxan (BNTFO-I) was designed and synthesized in a simple, and straightforward manner. Its isomer, 3,4-bis(4-nitrofuroxan-3-yl)furoxan (BNTFO-IV), was also obtained by isomerization.

Advances in Decarboxylative Oxidative Coupling Reaction.

Since carboxylic acid derivatives are commercially available, nontoxic, cheap, and normally stable to air and moisture, carboxylic acid derivatives are ideal reactants for synthetic strategy. In recent years, decarboxylative oxidative coupling reactions, which normally involve direct C-H bond activation, have attracted more and more interest from the synthetic community. Compared with conventional methods, this strategy is more environmentally friendly and step-economic.

Unactivated C(sp)-H Bond Functionalization of Alkyl Nitriles with Vinylarenes and Mechanistic Studies.

The first example of a metal-free unactivated C(sp)-H bond functionalization of alkyl nitriles with terminal vinylarenes to provide γ-ketonitrile derivatives is described. This protocol features simple operations, a broad substrate scope, and atom and step economy. In addition, Cu-catalyzed C(sp)-H bond functionalization of azodiisobutyronitrile (AIBN) and analogues with terminal vinylarenes to generate γ-ketonitriles was also studied.

An Unexpected Controlled New Oxidant: SO4(·-).

A controlled new oxidant sulfate radical anion (SO4(·-)) was found and it can be easily prepared by mixing Na2S2O4 and TBHP with stirring. In this new metal-free oxidation system (Na2S2O4/TBHP), SO4(·-) can be used as a controllable oxidant to oxidize various aromatic alcohols to the corresponding aldehydes in good yields without any acid formation at room temperature. SO4(·-) was determined by a DMPO (5,5-dimethyl-1-pyrroline-N-oxide) spin-trapping EPR method at room temperature on a Bruker E500 spectrometer and the results suggested that SO4(·-) was generated in this transformation.

Ligand-Mediated and Copper-Catalyzed C(sp(3))-H Bond Functionalization of Aryl Ketones with Sodium Sulfinates under Mild Conditions.

A novel and convenient copper (II) bromide and 1,8-diazabicyclo[5.4.1]undec-7-ene (DBU) or 1,10-phenanthroline catalysis protocol for the construction of α-alkyl-β-keto sulfones via C(sp(3))-H bond functionalization followed by C(sp(3))-S bond formation between aryl ketones and sodium sulfinates at room temperature has been developed.

A Petal-type Chiral NADH Model: Design, Synthesis and its Asymmetric Reduction.

A new type of NADH model compound has been synthesized by an efficient and convenient method. This model compound exhibits high reactivity and enantioselectivity in asymmetric reduction reactions. The results show that chiral NADH model S could be effectively combined with Mg(2+) to form ternary complexes.

Manganese-Mediated Coupling Reaction of Vinylarenes and Aliphatic Alcohols.

Alcohols and alkenes are the most abundant and commonly used organic building blocks in the large-scale chemical synthesis. Herein, this is the first time to report a novel and operationally simple coupling reaction of vinylarenes and aliphatic alcohols catalyzed by manganese in the presence of TBHP (tert-butyl hydroperoxide). This coupling reaction provides the oxyalkylated products of vinylarenes with good regioselectivity and accomplishes with the principles of step-economies.

Asymmetric Synthesis of 1,3-Oxazolidine Derivatives with Multi-Component Reaction and Research of Kinetic Resolution.

An efficient multi-component reaction to synthesize multi-substituted 1,3-oxazolidine compounds of high optical purity was described. All the products were well-characterized and the absolute configuration of one chiral center was determined. The plausible mechanism was proposed and a kinetic resolution of epoxides process was confirmed.

Copper/Manganese Cocatalyzed Oxidative Coupling of Vinylarenes with Ketones.

A novel copper/manganese cocatalyzed direct oxidative coupling of terminal vinylarenes with ketones via C(sp(3))-H bond functionalization following C-C bond formation has been developed using tert-butyl hydroperoxide as the radical initiator. Various ketones underwent a free-radical addition of terminal vinylarenes to give the corresponding 1,4-dicarbonyl products with excellent regioselectivity and efficiency through one step. A possible reaction mechanism has been proposed.

Selective nickel- and manganese-catalyzed decarboxylative cross coupling of some α,β-unsaturated carboxylic acids with cyclic ethers.

A nickel- and manganese-catalyzed decarboxylative cross coupling of α, β-unsaturated carboxylic acids with cyclic ethers such as tetrahydrofuran and 1, 4-dioxane was developed. Oxyalkylation was achieved when nickel acetate was used as catalyst, while manganese acetate promoted the reaction of alkenylation.

Stable acyclic aliphatic solid enols: synthesis, characterization, X-ray structure analysis and calculations.

A synthetic approach to stable enols was introduced and series of acyclic aliphatic solid enols were obtained and characterized. Relationship between the structure and the stability of these enols was discussed. Gaussian 09 calculations had been carried out to rationalize the stability of the enols.

Exploration on asymmetric synthesis of flavanone catalyzed by (S)-pyrrolidinyl tetrazole.

An improved method of the synthesis of flavanones catalyzed by pyrrolidine and BF(3) ·Et(2) O has been developed and a lot of flavanones could be easily synthesized via this method. The asymmetric synthesis of flavanone from benzaldehyde and 5-fluoro-2-hydroxyacetophenone has been studied and flavanone with moderate enantioselectivity was obtained in one step.

Synthesis of (2-oxoindolin-3-ylidene)methyl acetates involving a C-H functionalization process.

A novel palladium-catalyzed oxidative C-H functionalization protocol for the synthesis of (2-oxoindolin-3-ylidene)methyl acetates has been developed. In the presence of Pd(OAc)2 and PhI(OAc)2, a variety of N-arylpropiolamides underwent the C-H functionalization reaction with acids to afford the corresponding (E)-(2-oxoindolin-3-ylidene)methyl acetates selectively in moderate to excellent yields.

Sequential intermolecular aminopalladation/ortho-arene C-H activation reactions of N-phenylpropiolamides with phthalimide.

A novel palladium-catalyzed intermolecular aminopalladation/C-H activation method for selectively synthesizing (E)-(2-oxindolin-3-ylidene)phthalimides has been developed. In the presence of Pd(OAc)2 and PhI(OAc)2, alkynes were difunctionalized with a phthalimide and an arene sp2 C-H bond to selectively synthesize (E)-(2-oxoindolin-3-ylidene)phthalimides, which products are of great potential pharmaceutical value products in many major therapeutic areas, such as oncology, inflammation, neurology, immunology, and endocrinology. To the best of our knowledge, the reaction serves as the first example of intermolecular aminopalladation/C-H activation reactions of alkynes.

[Change of the trace elements content from cigarettes (tobacco) to its ash and to look at harm of stuck cigarette].

After the digestion of cigarettes and its ash are digested with concentrated nitric acid and perchloric acid, the change in mineral elements (Ca, Mg, Cu, Fe, Zn, Mn, Ni, Co, Cr, Pb and Cd) content in the cigarette and its ash were determined by flame atomic absorptionspectrophotometry. The experimental results showed that there were differences between the cigarette (tobacco) and its ash, especially, the contents of Pb and Cd harmful to human health in the ash are lowed 26.4% and 44.

A new type of NADH model compound: synthesis and enantioselective reduction of benzoylformates to the corresponding mandelates.

A new type of NADH model compound with good reactivity and enantioselectivity has been synthesized in good yields by an efficient and convenient synthetic method. The structures of these model compounds were confirmed by 1H and 13C-NMR and MS.

[Determination of inorganic elements in different parts of Sonchus oleraceus L by flame atomic absorption spectrometry].

Flame atomic absorption spectrometry with air-acetylene flame was used for the determination of inorganic metal elements in different parts ( flower, leaf, stem and root) of Sonchus oleraceus L. The contents of Ca, Mg, K, Na, Fe, Mn, Cu, Zn, Cr, Co, Ni, Pb and Cd in the flower, leaf, stem and root of Sonchus oleraceus L were compared. The order from high to low of the additive weight (microg x g(-1)) for the 13 kinds of metal elements is as follows: leaf (77 213.