- Solvent-free reactions of fullerenes with diethyl bromomalonate in the presence of inorganic bases under high-speed vibration milling conditions
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Solvent-free reactions of C60 and C70 with diethyl bromomalonate in the presence of various inorganic bases were investigated under the high-speed vibration milling (HSVM) conditions, and are shown to give methanofullerenes 1 and 2 in good to excellent yields based on consumed fullerenes. Several weak inorganic bases were found to be quite effective in promoting the solvent-free mechanochemical Bingel reactions of C60 and C70 under the HSVM conditions. Among the studied bases, sodium acetate gave the highest yield of monoadducts, while potassium carbonate afforded a considerable amount of bisadducts for both C60 and C 70.
- Peng, Ru-Fang,Wang, Guan-Wu,Shen, Ye-Bing,Li, Yu-Jin,Zhang, Ting-Hu,Liu, You-Cheng,Murata, Yasujiro,Komatsu, Koichi
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Read Online
- Unsymmetrical tetra-Acceptor-Substituted alkenes as polyfunctionalized building blocks: A divergent synthesis of densely functionalized pyrrolizines
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Various tetra-acceptor-substituted alkenes possessing unsymmetrical substituents have been effectively synthesized from vicinal tricarbonyl compounds. The alkenes have polyfunctionality and high electron deficiency. In addition, they easily react with pyrroles to give divergent pyrrolizine derivatives via the conjugate addition of pyrroles followed by intramolecular cyclization. We successfully controlled the chemoselectivity of the intramolecular cyclization (ester/ketone attack) to afford a wide range of valuable pyrrolizine derivatives.
- Asahara, Haruyasu,Kawakami, Shu,Yoshioka, Kotaro,Tani, Shinki,Umezu, Kazuto,Nishiwaki, Nagatoshi
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Read Online
- Atom-economic thiophosphoroselenenylations of C–H acid esters and amides
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Three improved thiophosphoroselenenylation procedures of CH-acids, including derivatives of malonic and acetyl-, phosphono-, 4-nitrophenyl- and 3-pyridylacetic acids, have been described and compared to previously reported thiophosphoroselenylation of diethyl malonate using bis(disopropoxyphosphinothioyl)diselenide alone or with the aid of methyl iodide. The use of iodine makes it possible to utilize both equivalents of the selenenylating agent. The procedures work well for the majority of nucleophiles in a pKa range between more acidic malononitrile or Meldrum acid and less acidic phenylacetates. The reaction carried out on diethyl malonate in boiling rectified ethanol yields selenoacetate, which cannot be obtained by direct phosphoroselenenylation. Crystal structure of one of the selenomalonamides confirms the stabilization effects of both carbonyl oxygens on selenium atom. The P-Se bond splitting, using TBAF in 3-molar excess in the presence of alkylating agent yields the respective C,Se-dialkyl derivatives.
- Majewski, Arkadiusz,Przychodzeń, Witold
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p. 3390 - 3402
(2021/11/17)
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- Photo/N-Heterocyclic Carbene Co-catalyzed Ring Opening and γ-Alkylation of Cyclopropane Enal
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An unprecedented photo/NHC-co-catalyzed ring-opening C-C bond cleavage of cyclopropane enal and the following γ-alkylation with a halogenated compound via radicals were established, affording the corresponding γ-alkylated α,β-unsaturated esters in moderate to good yields.
- Dai, Lei,Ye, Song
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supporting information
p. 986 - 990
(2020/02/28)
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- Convergent Synthesis of Dihydropyrans from Catalytic Three-Component Reactions of Vinylcyclopropanes, Diazoesters, and Diphenyl Sulfoxide
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A novel Rh(I)/La(III) cocatalytic three-component reaction of vinylcyclopropanes, diazoesters, and diphenyl sulfoxide has been developed. The reaction gives polysubstituted dihydropyrans as the reaction products. Mechanistic studies indicate that isomerization of vinylcyclopropanes gives conjugated dienes, which then undergo [4 + 2]-cycloaddition with vicinal tricarbonyl compounds generated by oxygen atom transfer from diphenyl sulfoxide to diazoesters.
- Zhang, Ya-Lin,Guo, Rui-Ting,Luo, Heng,Liang, Xin-Shen,Wang, Xiao-Chen
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supporting information
p. 5627 - 5632
(2020/07/14)
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- C–O bond formation via oxidative-coupling pathway in eutectic mixture of choline chloride/urea as a green solvent
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C–O bond formation between terminal alkenes/benzyl alcohols as an arylcarboxy surrogate and carbonyl compounds in a biodegradable deep eutectic solvent (DES) based on choline chloride and urea was performed. By employment of TBAI as catalyst and TBHP as oxidant, various derivatives of carbonyl compounds were benzylated in α position in good to high yield at 90 °C. Moreover, α-oxybenzoylation of diethyl malonate with carboxylic acids was performed in the above-mentioned DES by employment of NaI as the catalyst and TBHP as the oxidant at 60 °C.
- Saberi, Dariush,Manouchehri, Neda,Niknam, Khodabakhsh
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p. 680 - 687
(2019/01/03)
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- Synthesis of α-d-galactose-based azacrown ethers and their application as enantioselective catalysts in Michael reactions
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New chiral monoaza-15-crown-5 type macrocycles annelated to methyl 4,6-O-benzylidene-α-d-galactopyranoside have been synthesized. These crown ethers proved to be efficient catalysts in a few asymmetric reactions under mild phase transfer catalytic conditions. Michael adducts were formed with good to excellent enantioselectivities, so the addition of diethyl acetamidomalonate to β-nitrostyrene took place with up to 92% ee, while the reaction of diethyl acetoxymalonate with chalcones proceeded with up to 99% ee. Using diethyl bromomalonate as the nucleophile, the chiral cyclopropane derivatives were formed in up to 99% ee with the addition to chalcone, in up to 78% ee in the reaction with benzylidene malononitrile, and in up to 76% ee in the reaction with 2-benzylidene-1,3-diphenyl-1,3-propanedione applying α-d-galactoside-based crown ethers as the catalysts. In the Michael addition, the substituents of the chalcone had a considerable impact on the outcome of the reactions. Quantum chemical calculations have also been employed to evaluate the origin of the stereoselectivities.
- Rapi, Zsolt,Grün, Alajos,Keglevich, Gy?rgy,Stirling, András,Bakó, Péter
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p. 7856 - 7865
(2016/09/09)
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- Organocatalytic peroxidation of malonates, β-ketoesters, and cyanoacetic esters using n-Bu4NI/t-BuOOH-mediated intermolecular oxidative C(sp3)-O coupling
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A new organocatalytic approach for the synthesis of peroxides based on CH activation of a sp3-hybridized carbon atom is reported. Peroxides were prepared in 31-89% yield by the reaction of malonates, β-ketoesters, and cyanoacetic esters with a Bu4NI/tert-butyl hydroperoxide system. The formation of the expected hydroxylation products was not observed. In the discovered reaction, tert-butyl hydroperoxide plays a dual role by acting as the oxidant and the O-reagent for the C-O coupling. The synthesis can be scaled up to generate gram quantities of the target products.
- Terent'ev, Alexander O.,Zdvizhkov, Alexander T.,Levitsky, Dmitri O.,Fleury, Fabrice,Pototskiy, Roman A.,Kulakova, Alena N.,Nikishin, Gennady I.
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p. 8985 - 8990
(2015/11/02)
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- Enaminones via ruthenium-catalyzed coupling of thioamides and α-diazocarbonyl compounds
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Enaminones can be prepared via the Rh2(OAc)4- catalyzed coupling of α-diazocarbonyl compounds with thioamides. However, rhodium is the most expensive and least abundant among the dominant precious metals used for catalysis. Furthermore, a very limited substrate scope is known for the intermolecular rhodium catalyzed coupling reaction. Therefore, there is a need to find a more economical catalyst substitute with a broad substrate scope. In this paper, we describe the use of Ru(II) catalysts for the synthesis of enaminones. The reaction can be performed efficiently with the Grubbs first-generation catalyst or [(Ph)3P]3RuCl2 in a sealed tube. Both catalysts are much less expensive than Rh 2(OAc)4. Secondary and tertiary thioamides, when reacted with α-diazodiesters, α-diazoketoesters, α-diazodiketones, and α-diazomonoketones give enaminones. Primary thioamides give thiazole derivatives when reacted with α-diazomonoketones. However, with other diazo compounds, primary thioamides also give enaminones. All enaminones are obtained in good yields and with good diastereoselectivity. Accordingly, the method described in this paper is an efficient and economical alternative to the Rh2(OAc)4-catalyzed coupling process.
- Koduri, Naga D.,Wang, Zhiguo,Cannell, Garrett,Cooley, Kate,Lemma, Tsebaot Mesfin,Miao, Kun,Nguyen, Michael,Frohock, Bram,Castaneda, Maria,Scott, Halee,Albinescu, Dragos,Hussaini, Syed R.
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p. 7405 - 7414
(2014/09/17)
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- Sequential fullerenylation of bis-malonates-efficient access to oligoclusters with different fullerene building blocks
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A method for the sequential fullerenylation of bis-malonates with parent C60 and C2v-symmetric pentakis-adducts is reported. This approach relies on the finding that (a) chloromalonates can be used for the nucleophilic cyclopropanation of [6,6] double bonds of C60, and (b) chloromalonates, in contrast to bromomalonates, do not undergo base-catalyzed halogen exchange reactions. For the proof of concept, we synthesized a heptafullerene by using a divergent approach based on a fullerene hexakis-adduct with six bis-malonate addends in octahedral positions, each of which is suitable for an additional cyclopropanation of a fullerene building block. A sequence for the selective fullerenylation of bis-malonates with C60 and its exohedral C2v-symmetric pentakis-adducts has been developed. This method enables the straightforward synthesis of highly functional fullerene derivatives such as the heptafullerene 1.
- Wasserthal, Lennard K.,Kratzer, Andreas,Hirsch, Andreas
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p. 2355 - 2361
(2013/05/22)
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- Flame retardant properties of phosphorylated derivatives of malonic ester
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Thermal stability of the phosphorylated derivatives of malonic ester synthesized by the Michaelis-Becker reaction was studied. The flame-retardant efficiency of the phosphonomalonic ester was assessed by the flame-tube technique measuring the weight loss of wood samples impregnated with the studied compound.
- Sal'Keeva,Taishibekova,Minaeva,Shibaeva,Kasenov,Sal'Keeva,Muratbekova
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p. 659 - 662
(2013/07/27)
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- Bromophilic substitution/carbophilic substitution cascade reactions of α,α-dibromo-2-methoxyacetophenone with C-, N- and O-nucleophiles
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α,α-Dibromo-2-methoxyacetophenone reacts, under mild reaction conditions, with C-, N- and O-nucleophiles via a bromophilic substitution/protonation/carbophilic substitution cascade process to afford α-monosubstituted-2-methoxyacetophenones in moderate to good yield. The only exception from this reaction pathway is the reaction with the anion derived from malononitrile in which 2-aroyl-1,1,3,3-tetracyanopropene is obtained.
- Tatar, Jovana,Markovi?, Rade,Stojanovi?, Milovan,Baranac-Stojanovi?, Marija
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experimental part
p. 4851 - 4855
(2010/10/02)
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- Reactions of distabilized β-dicarbonyl sulfonium and iodonium ylides with isocyanates
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The reactions of tosyl isocyanate with diethyl diphenylsulfuranylidenemalonate, 2-dimethylsulfuranylidenedimedone, and 2-dimethylsulfuranylideneindane-1,3-dione afforded 1,3-ditosyl-5,5- diethoxycarbonylimidazolidine-2,4-dione and tosylimination products at the keto groups, respectively. Phenyliodonium ylides derived from diethyl malonate and ethyl acetate react with 3,4-dichlorophenyl isocyanate to form substituted oxazolin-2-ones. Springer Science+Business Media, Inc. 2006.
- Gololobov,Golding,Galkina,Lokshin,Garbuzova,Petrovskii,Starikova,Averkiev
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p. 883 - 891
(2008/02/04)
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- Studies on synthesis of 3(2H)-benzofuranone derivatives
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Two known methods were used for synthesis of 2,6-disubstituted-3(2H)-benzofuranone derivatives. It was found that depending on the reaction conditions, degradation products or the products of oxidation were isolated. This latter reaction became the main process when the ring closure was performed starting from methoxy- or 2-propoxy-desoxybenzoin and diethyl bromo-(or chloro-)-malonate to give D,L- and meso-dimers of the substituted 3(2H)-benzofuranones.
- Bokotey, Sandor,Koevari-Radkai, Maria,Podanyi, Benjamin,Ritz, Imola,Hanusz, Miklos,Batori, Sandor
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p. 2325 - 2343
(2007/10/03)
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- Simple synthesis of tetra-acceptor-substituted alkenes by the formal dehydrodimerization of malonates
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Only two steps are required for the synthesis of tetra-acceptor- substituted alkenes from simple malonates in excellent yields [Eq. (1)]. The method is characterized by cheap and commercially available precursors, and ultrasound remarkably accelerates the radical reaction as well as the successive Knoevenagel reaction.
- Linker, Torsten,Linker, Ursula
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p. 902 - 904
(2007/10/03)
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- Electrochemical oxidation of malonic esters in acetonitrile in the presence of iodides as mediators
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Electrochemical oxidation of malonic esters in acetonitrile in the presence of iodides follows two different pathways depending on the nature of the cation. In the presence of LiI, alkyl 1,1,2,2,3,3-propanetetracarboxylates were obtained in 85-98% yields. In the presence of NaI, KI, or Bu4NI, the formation of 1,1,2,2-ethanetetracarboxylates and their subsequent dehydrogenation to ethenetetracarboxylates was the main reaction pathway.
- Fedukovich,Elinson,Nikishin
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p. 599 - 602
(2007/10/03)
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- Reactions od Arylazosulfones with the Conjugate Bases of Active-Methylene Compounds
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The reaction between arylazo p-tolyl sulfones 1a-f (Ar-N=N-SO2-p-Tol) and the potassium salts of some active-methylene compounds (CH2XY: X, Y = CN, COOEt) represents an example of unprecedented behaviour of azosulfones and effectively leads, depending on the nucleophile, to either unsymmetrical (6-8) or symmetrical (9) tetrasubstituted ethylenes.Of particular interest is the possibility to synthesize, in high yields and mild conditions, polarysed ethylenes some of which are otherwise not easily accessible.A mechanism involving successive condensation processes is supported by experimental evidence.
- Dell'Erba, Carlo,Novi, Marino,Petrillo, Giovanni,Tavani, Cinzia
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p. 3905 - 3914
(2007/10/02)
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- The photolytic disproportionation of dialkyl 2,2-di(phenylseleno)propanedioates
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Dialkyl-2,2-di(phenylseleno)propanedioates undergo disproportionation to form tetralkyl 1,1,2,2-ethylene tetracarboxylates and diphenyl diselenide upon photolysis. Evidence for the intermediacy of a capto-dative radical intermediate in this process is described.
- Byers,Thissell
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- Potassium fluoride on alumina: Oxidative coupling of acidic carbon compounds with diiodine
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Diiodine reacts at room temperature with activated methylene compounds in the presence of potassium fluoride on alumina and saturated dimers, unsaturated dimers or trimers were formed according to the stoechiometry of the reaction. The reactions were improved by using ultrasound activation.
- Villemin,Alloum
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p. 3169 - 3179
(2007/10/02)
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- Formation of isoxazolines N-oxides and dihydrofurans from a cyclocondensation between bromo or chloromalonate carbanion and Michael acceptors
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Heterocyclic compounds are prepared by a cyclocondensation reaction between halomalonate carbanion and Michael acceptors : α-nitroalkenes lead to isoxazolines N-oxides and α,β-unsaturated carbonyl derivatives to dihydrofurans.Formation of the carbanion results from deprotonation of monohalomalonates with powdered potassium carbonate in THF; as a rule; chloromalonate affords better yields than bromomalonate.Key Words: halomalonate carbanions / electrophilic alkenes / dihydrofurans / isoxazolines N-oxide
- Menn, J. C. Le,Sarrazin, J.,Tallec, A.
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p. 562 - 565
(2007/10/02)
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- Preparation and Cycloaddition Chemistry of Thio- and Selenocarbonyls Derived from Reaction of Elemental Sulfur and Selenium with Stabilized α-Halo Anions
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Reaction of diethyl chloromalonate with Cs2CO3 in the presence of elemental S8 or Sen generates the corresponding diethyl thioxo- or selenoxomalonates which are subsequently trapped in situ with various 1,3-dienes.Similarly, the chalcogen carbonyls can be prepared from other halogenated compounds using DBU as the base and effectively trapped in Diels-Alder fashion with 2,3-dimethyl-1,3-butadiene (Table 2).
- Abelman, Matthew M.
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p. 7389 - 7392
(2007/10/02)
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- GENERATION AND DIENOPHILIC REACTIVITY OF α-OXOSELENOALDEHYDES AND KETONES
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The reaction elemental selenium with sulfur ylides stabilized by electron-withdrawing substituent(s) affords a facile method for generation of functionalized selenocarbonyl compounds, which can be effectively trapped by Diels-Alder reaction with 1,3-dienes.
- Nakayama, Juzo,Akimoto, Keiichi,Niijima, Jun,Hoshino, Masamatsu
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p. 4423 - 4426
(2007/10/02)
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- Effects of strong π-electron accepting substituents on structure preference for thiocarbonyl ylide or thiirane
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Equilibrium between thiocarbonyl ylide and thiirane depends upon the π-electron accepting nature of the substituents. Four carbonyl and ester groups move the equilibrium far to the thiocarbonyl ylide side.
- Oka, Kitaro,Dobashi, Akira,Hara, Shoji
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p. 3579 - 3582
(2007/10/02)
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- SYNTHESIS OF gem-DIALKOXYCARBONYLCYCLOPROPANE DERIVATIVES FROM OLEFINS BY THE REACTION WITH DIBROMOMALONIC ESTERS AND COPPER IN DIMETHYL SULPHOXIDE
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A novel method for the synthesis of gem-dialkoxycarbonylcyclopropane derivatives is reported which involves the reaction of olefins with dibromomalonic esters and Cu in dimethyl sulphoxide.The reaction was applicable to a wide range of olefins and proceeded smoothly at moderate temperature to give the cyclopropane derivatives often in good yields.Cu was converted to Cu(II) bromide during the reaction.The reaction was weakly electrophilic and proceeded non-stereospecifically, and a stepwise mechanism involving addition and elimination appeared favourable for the reaction.In contrast, in the previously reported examples of the cyclopropanation of olefins by organic gem-dihalides and Cu in an aromatic hydrocarbon, Cu was concerted to Cu(I) halides and a concerted cycloaddition of carbenoid intermediates appeared favourable.
- Kawabata, Nariyoshi,Tanimoto, Masami
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p. 3517 - 3522
(2007/10/02)
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