A facile synthesis of 1,7-dicarbonyl compounds via three-component Michael addition reactions

A convenient one-pot synthesis of 1,7-dicarbonyl compounds has been accomplished by a three-component Michael addition reaction of nitromethane with two unsymmetric α,β-unsaturated carbonyl compounds in the presence of a base.     

An atom-economic synthesis of functionalized pyrroles via a sequential metal-catalyzed three-component reaction

A three-component reaction of one molecule of imine and two molecules of alkynoates is realized with the catalysis of Cu(I)–Fe(III) in a sequential manner to allow the direct synthesis of functionalized pyrroles, during which, one C–N bond and two C–C bonds are formed with high atom economy. This method benefits from easily available starting materials, low-cost catalysts, and convenient operations.     

On-line mass spectrometric analysis of hydrothermal reactions for biomass model sample containing sulfur compounds

Biomass gasification using supercritical water is a promising way to produce hydrogen gas. However, this method might release toxic heteroatomic compounds. It is therefore important to clarify reaction pathways for efficiently obtaining hydrogen gas and suppressing environmental burden. L-cysteine was adopted for a test reagent containing sulfur and determination of the sulfur compound reaction pathways was studied by Li⁺-ion attachment mass spectrometry. It was found that H₂S, CO, CO₂, SO, SO₂ and SO₃ gasses were released at high concentrations in the gas phase during the hydrothermal reaction. By adding Ca(OH)₂ as alkali, the pathway of these gasses were, however, suppressed into the liquid phase so that the toxic emissions to the gas phase could be avoided.     

Estimation of the activity of catalysts and the reactivity of organosulfur compounds

The kinetics of hydrogenolysis of various classes of organosulfur compounds were studied in the presence of MeAlCl ₄ catalysts (Me=Li, Na, K). The reactions were conducted at 100–250°C without introduction of hydrogen into the reaction zone, but in the presence of hydrocarbons capable of acting as hydride—ion donors; these donors were necessary for H ₂ S formation. A series of catalytic activities and optimal reaction conditions for each catalyst were determined from the rate constants of hydrogenolysis at the C-S bond. Reactivities of mercaptans, sulfides, disulfides, and thiophene were estimated.Institute of Chemistry, Bashkir Scientific Center, Ural Branch, Russian Academy of Sciences, Ufa 450054. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 3, pp. 562–564, March, 1992.     

Addition reactions of a phosphorus triamide to nitrosoarenes and acylpyridines

Abstract

Tricoordinate phosphorus compounds react with a wide variety of double bonds through addition reactions. The dipolar and cyclic products formed are important intermediates in organophosphorus chemistry. We investigated the reactivity between phosphorus triamide 1 and nitrosoarenes and 2-acylpyridines. For sterically congested substrates, the formation of σ⁵ Aroyan, C. E.; Dermenci, A.; Miller, S. J. The Rauhut–Currier Reaction: A History and Its Synthetic Application. Tetrahedron 2009, 65, 4069–4084. DOI: 10.1016/j.tet.2009.02.066.[Crossref], [Web of Science ®] , [Google Scholar],λ⁵-phosphorus products is observed. DFT calculations indicate this product is formed through a concerted [4?+?1] mechanism. For less sterically congested substrates, products are observed arising from cleavage of the N?=?O or C?=?O bond with formation of a terminal P?=?O bond and aryl nitrene or carbene migration into a P–N bond of the phosphorus triamide core. DFT calculations are consistent with an initial [2?+?1] addition to phosphorus followed by formal carbene/nitrene migration in these cases.     

An efficient method for synthesis of stable phosphorus ylides and 1,4-diionic organophosphorus compounds in the presence of sodium dodecyl sulfate in aqueous media

Stable crystalline phosphorus ylides and 1,4-diionic organophosphorus compounds were obtained in good to excellent yields from the 1:1:1 addition reaction between triphenylphosphine, dialkyl acetylenedicarboxylates and β-dicarbonyl or heterocyclic compounds, such as diethyl malonate, acetyl acetone, 1,3-diphenyl propane-1,3-dione, 1,3-dimethylbarbituric acid, meldrum’s acid, 2-benzoxazolinone, benzotirazole, and 2-thiazoline-2-thiol in the presence of sodium dodecyl sulfate as a surfactant in water. Green synthesis, mild conditions, decreasing timescale of reaction, low cost, and easy workup are the main advantages of this method.     

Organometallic synthesis in the furazan series. 4. Reactions of azofurazans with organolithium compounds

The reactions of azofurazans, including macrocyclic azofurazans, with BuⁿLi and Li derivatives of methylfurazans were studied. Several competitive processes were found to occur: the addition of a Li reagent at the N=N bond, the redox reaction giving rise to hydrazofurazans, and the reaction of the side chain of azofurazan.     

Efficient synthesis of polysubstituted pyrrole-3-carbonitriles via reactions of 1,1-dicyano-2,3-diarylcyclopropanes with aromatic imines

Co(ClO₄)₂ smoothly catalyzed the reactions of 1,1-dicyano-2,3-diarylcyclopropanes with aromatic imines to give the novel polysubstituted pyrrole-3-carbonitriles bearing an 2-arylidenimino group in good to high yields in refluxing THF.     

Three characteristic reactions of alkynes with metal compounds in organic synthesis

Alkynes have two sets of mutually orthogonal π‐bonds that are different from the π‐bonds of alkenes. These π‐bonds are able to bond with transition metal compounds. Alkynes easily bond with the various kinds of compounds having a π‐bond such as carbon monoxide, alkenes, other alkynes and nitriles in the presence of the transition metal compounds. The most representative reaction of alkynes is called the Pauson–Khand reaction. The Pauson–Khand reactions include the cyclization of alkynes with alkenes and carbon monoxide in the presence of cobalt carbonyls. Similar Pauson–Khand reactions also proceed in the presence of other transition metal compounds. These reactions are the first type of characteristic reaction of alkynes. Other various kinds of cyclizations with alkynes also proceed in the presence of the transition metal compounds. These reactions are the second type of characteristic reaction of alkynes. These include cyclooligomerizations and cycloadditions. The cyclooligomerizations include mainly cyclotrimerizations and cyclotetramerizations, and the cycloadditions are [2 + 2], [2 + 2 + 1], [2 + 2 + 2], [3 + 2], [4 + 2], etc., type cycloadditions. Alkynes are fairly reactive because of the high s character of their σ‐bonds. Therefore, simple coupling reactions with alkynes also proceed besides the cyclizations. The coupling reactions are the third type of characteristic reactions of alkynes in the presence of, mainly, the transition metal compounds. These reactions include carbonylations, dioxycarbonylations, Sonogashira reactions, coupling reactions with aldehydes, ketones, alkynes, alkenes and allyl compounds. Copyright © 2008 John Wiley & Sons, Ltd.     

Stereoselective approach to conjugated enone oximes from aliphatic nitro compounds and sulfur ylides

A novel approach to conjugated enone oximes from aliphatic nitro compounds deals with double silylation of N,N-bis(silyloxy) enamines followed by a stereoselective reaction with an ester-stabilized sulfur ylide. The proposed mechanism involves the generation of labile nitrosoalkenes as intermediates, which react with the sulfur ylide to give target enone oximes.     

Characteristic reactions of group 9 transition metal compounds in organic synthesis

Group 9 metal compounds in organic synthesis have two characteristic reactions. The first occurs because the group 9 metals have a high affinity to carbon–carbon or carbon–nitrogen π‐bonds. The first type of characteristic reactions in these group 9 metal compounds includes Pauson–Khand reactions, the Pauson–Khand‐type reactions ([2 + 2 + 1] cyclization), the other cyclizations and coupling reactions. The second occurs because the group 9 metals have a high affinity to carbonyl groups. The second type of characteristic reactions includes carbonylations such as hydroformylations, the carbonylations of methanol, amidocarbonylations and other carbonylations. The first characteristic reactions are applied for the synthesis of fine chemicals such as pharmaceuticals and agrochemicals. However, the second characteristic reactions are utilized not only for fine chemicals but also for important bulk commodity chemicals such as aldehydes, carboxylic acids and alcohols. Copyright © 2009 John Wiley & Sons, Ltd.     

Catalytic asymmetric synthesis of glycidic amides via chiral sulfur ylides

Reaction of diazoacetamides with aromatic aldehydes in the presence of 20 mol% of chiral binaphthylsulfide and 10 mol% of copper(II) acetylacetonate gave chiral glycidic amides with up to 64% ee.     

An efficient protocol for the synthesis of benzoheterocyclic compounds via solid-state melt reaction (SSMR)

An efficient protocol for the synthesis of biologically active benzoheterocyclic compounds such as benzothiazoles, benzimidazoles, benzospirothiazoles, and quinoxaline scaffolds have been accomplished via solid state melt reaction (SSMR) with excellent yields. The new protocol does not require any catalyst, solvent, and workup. Two anti-tumor agents have been prepared to demonstrate the application of this new method.     

Pd催化交叉偶联P-C键形成反应

近30年来,Pd催化交叉偶联形成P-C键的反应在药物、催化剂配体、阻燃剂和高分子材料等领域受到普遍重视。本文介绍了Pd催化交叉偶联反应形成P-C键的方法,以及利用该法制备有机膦化合物的研究进展。作为反应底物的磷亲核试剂包括亚磷酸二烷基酯、亚膦酸酯、次膦酸酯、氧化膦、伯或仲膦、三芳基膦、亚磷酸三烷基酯、膦-硅(锡)化合物和膦-硼烷复合物等,参与偶联反应的亲电试剂包括卤代烯烃、卤代芳烃、三氟甲磺酸烯基酯、三氟甲磺酸芳基酯、乙烯基硼酸酯等,并对反应机理、反应条件和反应的影响因素进行了探讨。     

多组分反应合成杂环化合物研究进展

利用多组分反应合成结构复杂多样的杂环化合物,在有机合成领域具有广阔的应用前景和研究价值.本文综述了近年来多组分反应在五元杂环、六元杂环、多元杂环合成中的研究进展,同时对杂环化合物的绿色合成方法做出展望.     

A simple and efficient approach to the synthesis of highly functionalized fused benzochromenes

Protonation of the reactive intermediates produced in the reaction between tert-butyl isocyanide and dimethyl acetylenedicarboxylate or dibenzoylacetylene, by 1-naphthol, 2-naphthol, 2,3-dihydroxynaphthalene, 2,7-dihydroxynaphthalene or 4-methyl-8-hydroxycoumarin leads to vinylnitrilium cations, which undergo carbon-centered Michael type addition with the conjugate base of the naphthols to produce highly functionalized benzochromenes.