Synthesis of (E)-2-chlorovinyltellurium trichloride and (E,E)-bis(2-chlorovinyl) ditelluride

The reaction of tellurium tetrachloride with acetylene in CCl₄ at atmospheric pressure and ambient temperature affords earlier unknown (E)-2-chlorovinyltellurium trichloride in 30% yield, whose reduction with sodium bisulfite gives (E,E)-bis(2-chlorovinyl) ditelluride in 64% yield.     

Vinylation of hydroxy-containing cyclic formaldehyde acetals with acetylene

Nucleophilic addition of alcohols having cyclic acetal fragments to acetylene smoothly occurs under relatively mild conditions (KOH, 100–125°C, 1–2 h, initial acetylene pressure 11–12 atm) to give the corresponding vinyl ethers in 80–83% yield.     

Tuneable superbase-catalyzed vinylation of α-hydroxyalkylferrocenes with alkynes

Superbase-catalyzed (KOH/DMSO suspension as a catalyst) vinylation of hydroxymethyl- and hydroxyethylferrocenes with terminal and internal alkynes (acetylene, propyne, phenylacetylene, 3-ethynylpyridine, 1-propyn-1-yl-benzene, diphenylacetylene) affords hitherto unknown vinyl ethers of ferrocene in 30–93% yields depending on the alkyne structure and the tuneable ratio of reactants/KOH/DMSO. The vinylation smoothly proceeds under mild conditions (70–90 °C, 0.25–13 h). With unsubstituted acetylene the process is readily realized under atmospheric pressure (yield of the corresponding vinyl ethers is 81–90%) though under pressure (initial pressure at room temperature is 10–13 atm, maximum pressure is 13–16 atm at the reaction temperature) the yield is close to quantitative (93%). The synthesized compounds were characterized using ¹H and ¹³C NMR, and IR spectroscopy, as well as X-ray diffraction analysis.     

微波等离子体下甲烷偶联制乙炔的研究

通过优化设计矩形波导谐振腔微波化学反应器,可以大幅提高微波等离子体下甲烷转化率（最高为93．7％）、C2烃收率（最高为91．0％）和乙炔收率（最高为88．6％）．且优化后,在实验的压强范围内,甲烷转化率和C2烃收率较为稳定,C2烃主要是乙炔,其选择性都在90％以上．生成乙炔的能量产率和时空产率也都比较高．利用发射光谱法对微波等离子体下甲烷偶联制乙炔的反应进行了诊断研究,在300nm～750nm波长范围内激发态物种有：CH,C2,H2,Hα-根据反应产物和激发态物种从化学反应热力学和动力学上对反应机理进行了初步探索．     

Stereoselective synthesis of functionalized divinyl sulfides based on sulfur dichloride and (trimethylsilyl)acetylene

Sulfur dichloride reacts with (trimethylsilyl)acetylene to form stereoselectively E, E-bis-(2-chloro-2-trimethylsilylvinyl) sulfide and isomeric E-2-chloro-2-trimethylsilylvinyl E-2-chloro-1-trimethylsilylvinyl sulfide. Desilylation of these compounds provides an individual E, E-bis-(2-chlorovinyl) sulfide.

     

Transformations of 5-(2-arylethynyl)-2-methyl-2H-tetrazoles under superelectrophilic activation

Reaction of 5-arylethynyl-2-methyl-2H-tetrazoles (acetylene tetrazoles) with arenes under the action of Brønsted superacid CF₃SO₃H or acidic zeolite HUSY CBV-720 gives rise to E-/Z-5-(2,2-diarylethenyl)-2-methyl-2H-tetrazoles, as products of hydroarylation of acetylene bond, in yields up to 98% with predominant formation of E-isomers. Cationic intermediates of these reactions have been studied theoretically by DFT calculations. Addition of CF₃SO₃H to the triple bond of acetylene tetrazoles leads to the corresponding E-/Z-vinyl triflates in high yields. Hydration of triple bond in these tetrazoles in H₂SO₄ results in the formation of 5-(2-aryl-2-oxoethyl)-2-methyl-2H-tetrazoles. Tandem hydroarylation-ionic hydrogenation of acetylene tetrazoles in the systems acid(CF₃SO₃H or AlCl₃)-arene-cyclohexane affords 5-(2,2-diarylethyl)-2-methyl-2H-tetrazoles.     

Efficient synthesis of β-chlorovinylketones from acetylene in chloroaluminate ionic liquids

A method for the Friedel-Crafts-type insertion reaction of acetylene with acid chlorides in chloroaluminate ionic liquids is presented. The use of ionic liquids not only serves to avoid the use of carbon tetrachloride or 1,2-dichloroethane but also suppresses side reactions, notably the polymerization of acetylene, which occurs in these chlorinated solvents. Consequently, the products can be isolated using a simpler purification procedure, giving a range of aromatic and aliphatic β-chlorovinyl ketones in high yield and purity.     

One-pot assembly of 4-methylene-3-oxa-1-azabicyclo[3.1.0]hexanes from alkyl aryl(hetaryl) ketoximes, acetylene, and aliphatic ketones: a new three-component reaction

A new three-component reaction between alkyl aryl(hetaryl)ketoximes, acetylene, and aliphatic ketones in the superbasic systems KOH/DMSO and LiOH/CsF/DMSO (70-90 °C, initial acetylene pressure 13-15 atm, 5-60 min) affords novel 4-methylene-3-oxa-1-azabicyclo[3.1.0]hexanes in yields of up to 75%. Using KOH/DMSO, the side products of the reaction are O-vinylketoximes and 2-aryl(hetaryl)pyrroles, while with LiOH/CsF/DMSO, the reaction proves to be selective, only minor amounts of the corresponding alkyl aryl(hetaryl) ketones being detectable.     

A short-cut from 1-acetyl adamantane to 2-(1-adamantyl)pyrroles

The oxime of 1-acetyl adamantane 2 is added to acetylene (KOH/DMSO, 70 °C, initial acetylene pressure 13 atm, 30 min) to afford the corresponding O-vinyl oxime 5 in 80% yield. The latter upon heating (DMSO, 120 °C, 1 h) gives 2-(1-adamantyl)pyrrole 3, 1-acetyl adamantane 1, and adamantane (6:3:1 mass ratio), the yield of the pyrrole 3 being 83% (based on 1-acetyl adamantane 1 consumed). Under harsher conditions (NaOH/DMSO, 130 °C, atmospheric pressure of acetylene, 4 h) oxime 2 reacts with acetylene to furnish pyrrole 3, 1-acetyl adamantane 1, 1-vinyl adamantane 9, and adamantane (6:7:3:1 mass ratio), with the isolated yield of pyrrole 3 reaching 34%. Under pressure (NaOH/DMSO, 120 °C, initial acetylene pressure 14 atm, 1 h) the same reaction leads to 2-(1-adamantyl)-1-vinylpyrrole 4 and ketone 1 in 48% (based on consumed ketone 1) and 24% yields, respectively. The pyrrole 4 is easily deprotected to the corresponding 1H-pyrrole 3 in 77% yield by treatment (aqueous MeCN) with Hg(OAc)₂ and NaBH₄.     

碲化银纳米晶的室温合成及表征

在室温下制备了碲化银纳米粒子,制备过程中选用了新型的还原剂多聚甲醛。所得产物用X射线光电子能谱、X射线粉末衍射和透射电镜进行了表征。     

Acetylene derivatives. Communication 177. Condensation of aromatic and aliphatic-aromatic ketones with acetylene under pressure. Part III.

Summary In presence of potassium hydroxide powder, aliphatic-aromatic and aromatic ketones of the aceto- and benzo-phenone types condense smoothly with acetylene at a pressure of 5–10 atm with formation of the corresponding tertiary acetylenic alcohols in yields of more than 90%. When the 2-aryl-3-butyn-2-ols so obtained are selectively hydrogenated over a palladium catalyst, 2-aryl-3-buten-2-ols are obtained in almost quantitative yield, and dehydration of these gives 2-aryl-1,3-butadienes, which are extremely reactive in polymerization (dimerization) reactions and in the diene condensation.     

C-S bond cleavage of pyridine-2-thiol: a new functionality of quadruply bridged dinuclear platinum and palladium complexes

Treatment of pyridine-2-thiol (pytH) with H(2) (60 atm) in the presence of 5-methylpyridine-2-thiolate (5-mpyt)-bridged dinuclear Pt(III), Pt(II), or Pd(II) complexes (1 mol %) in DMF at 150 degrees C for 72 h leads to the formation of pyridine in 3-51% yield. From the (1)H NMR study of the exchange reactions and of the products under D(2) pressure, it is suggested that the catalytic reaction involves bimetallic activation of the pyt ligand followed by the liberation of pyridine and H(2)S.     

Selective reduction of imonium salts by sodium hydrogen telluride

Sodium hydrogen telluride reduces imonium salts effeciently at room temperature in ethanol. The products of the reaction depend upon the pH. Under alkaline pH only dihydro-derivatives are formed. Under acid pH (6-7) the products depend on the structure of the salt. The tellurium con be recovered quantitatively.     

Carbonylative cross-coupling reaction of ethynylstibane with aryl iodides

Palladium-catalyzed carbonylative cross-coupling reaction of ethynylstibane (PhSbPh(2)) and aryl iodides (Ar-I) is described. The reaction of the stibanes and the halides under 1 atm of carbon monoxide in N,N-dimethylacetamide using a combination of 5 mol% Pd(OAc)(2) and 4 equivalents (20 mol%) of PPh(3) brought about carbonylative cross-coupling reaction to afford arylethynylketones [ArC(O)Ph] in good yields along with a small amount of directly coupled products, aryl acetylens (ArPh). Formation of the side product was completely suppressed by conducting the reaction under high CO pressure (20 atm) conditions. The present method provides a variety of carbonylated products in good yield even with electron-deficient aryl iodides which usually give inferior results due to their tendency to undergo decarbonylation in the cross-coupling reaction of ethynylstibanes and acyl halides.     

anti-Markovnikov addition of tellurium tetrachloride to trimethyl ethynyl silane

An investigation of the TeCl₄ interaction with trimethyl ethynyl silane 1 in CHCl₃ has shown that anti-Markovnikov adduct [Z-1-(trimethylsilyl)-2-chlorovinyl]tellurium trichloride is formed as the only product. In time, it is hydrolyzed to give [Z-1-(trimethylsilyl)-2-chlorovinyl]tellurium (hydroxy) dichloride which, in turn, is dehydrated to afford bis[(2-chloro-1-trimethyl-silylvinyl)dichlorotellurium]oxide. These data revealed that the reaction studied was the first example of anti-Markovnikov syn-addition of TeCl₄ to terminal acetylenes. A computed simulation of the TeCl₄ interaction with ethynyl silane 1 in a gas state using PES method did not reveal dominating orientation of the addition but showed the conditions at which anti-Markovnikov addition can occur and which were probably met in carrying out the reaction in CHCl₃.     

The atmospheric photolysis of E-2-hexenal, Z-3-hexenal and E,E-2,4-hexadienal

The atmospheric photolysis of E-2-hexenal, Z-3-hexenal and E,E-2,4-hexadienal has been investigated at the large outdoor European Photoreactor (EUPHORE) in Valencia, Spain. E-2-Hexenal and E,E-2,4-hexadienal were found to undergo rapid isomerization to produce Z-2-hexenal and a ketene-type compound (probably E-hexa-1,3-dien-1-one), respectively. Both isomerization processes were reversible with formation of the reactant slightly favoured. Values of j(E-2-hexenal)/j(NO(2)) = (1.80 +/- 0.18) x 10(-2) and j(E,E-2,4-hexadienal)/j(NO(2)) = (2.60 +/- 0.26) x 10(-2) were determined. The gas phase UV absorption cross-sections of E-2-hexenal and E,E-2,4-hexadienal were measured and used to derive effective quantum yields for photoisomerization of 0.36 +/- 0.04 for E-2-hexenal and 0.23 +/- 0.03 for E,E-2,4-hexadienal. Although photolysis appears to be an important atmospheric degradation pathway for E-2-hexenal and E,E-2,4-hexadienal, the reversible nature of the photolytic process means that gas phase reactions with OH and NO(3) radicals are ultimately responsible for the atmospheric removal of these compounds. Atmospheric photolysis of Z-3-hexenal produced CO, with a molar yield of 0.34 +/- 0.03, and 2-pentenal via a Norrish type I process. A value of j(Z-3-hexenal)/j(NO(2)) = (0.4 +/- 0.04) x 10(-2) was determined. The results suggest that photolysis is likely to be a minor atmospheric removal process for Z-3-hexenal.     

Asymmetric Pauson-Khand-type reaction mediated by Rh(I) catalyst at ambient temperature

An efficient asymmetric PKR mediated by Rh(I) catalyst at ambient temperature was developed. The reaction utilizing a Rh(I) catalyst bearing a (R)-3,5-diMeC4H4-BINAP ligand at 18-20 degrees C under a reduced partial pressure of CO (0.1 atm) provided PKR products in high chemical yield as well as high enantioselectivity.     

Tellurium-mediated cycloaromatization of acyclic enediynes under mild conditions

The cycloaromatization of acyclic enediynes typically requires very high temperatures (>160 degrees C) and dilute conditions to proceed in a synthetically useful yield. These conditions hinder reaction throughput, inhibiting the use of this reaction for the large-scale production of materials. The reaction of sodium telluride with acyclic arenediynes yields the corresponding tellurepine, which under gentle heating extrudes Te degrees to yield the cycloaromatization product. We have developed conditions that form sodium telluride from inexpensive tellurium metal in situ, and that also perform the desilylation of silylated arenediynes in the same process. Under our conditions, we are able to perform desilylation and cycloaromatization at temperatures as low as 40 degrees C and on a scale as large as 5 g in standard laboratory glassware.     

A Convenient Method of Synthesis of Dialkyltellurides and Dialkylditellurides

Elemental tellurium is reduced by thioureadioxide in alkaline medium, leading to disodium telluride or ditelluride, depending on the amount of thioureadioxide used. The intermediate disodium telluride or ditelluride reacts “in situ” with alkyl halides to give dialkyltellurides or dialkylditellurides in high yield.     

Diels-Alder cycloaddition of acetylene gas to a polycyclic aromatic hydrocarbon bay region

The direct conversion of a polycyclic aromatic hydrocarbon bay region to a new, unsubstituted benzene ring by Diels-Alder cycloaddition of acetylene gas is reported for the first time. At 140 °C in dimethylformamide, under 1.8 atm pressure of acetylene gas, 7,14-dimesitylbisanthene is slowly converted to 7,14-dimesitylbenzo[ghi]bisanthene (21% conversion in 48 h).