- Cross coupling of sulfonyl radicals with silver-based carbenes: A simple approach to β-carbonyl arylsulfones
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A coupling reaction between sulfonyl radicals and silver-based carbenes has been well established. This simple radical-carbene coupling (RCC) process provided an efficient approach to a variety of β-carbonyl arylsulfones from sodium arylsulfinates and diazo compounds, and was characterized by wide substrate scope, easy scale-up, simple manipulation, accessible starting materials, and mild reaction conditions.
- Li, Jingjing,Lian, Pengcheng,Wan, Xiaobing,Wang, Hanghang,Zheng, Yonggao
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supporting information
p. 2163 - 2169
(2020/03/27)
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- A simple criterion for gas chromatography/mass spectrometric analysis of thermally unstable compounds, and reassessment of the by-products of alkyl diazoacetate synthesis
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Rationale: A principal limitation of gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS) is the thermal instability of analytes. We propose that the injector and column temperatures should not exceed the atmospheric pressure boiling point, without decomposition, of the highest homologue of the series being analyzed, instead of the time-consuming procedure of obtaining chromatograms using different temperatures. Methods: A series of thermally unstable diazocarbonyl compounds, alkyl diazoacetates (predicted limit of stability approx. 140 °C, the boiling point of ethyl diazoacetate), was selected for GC/MS analysis using standard equipment. Different GC separation conditions were selected so that the retention temperatures of target compounds were both below and above 140°C. Results: Analyzing alkyl diazoacetates within their thermal stability range permitted reanalysis of their typical synthesis by-products. No dialkyl fumarate or maleate impurities, principal decomposition products which have often been reported previously, were found. Instead, alkyl esters of glycolic acid nitrate, O2NOCH 2CO2R, and 'pseudo-dimeric' products, ROCO[C 2H3NO]CO2R, were discovered for the first time. Conclusions: Avoiding the decomposition of thermally unstable organic compounds during GC and/or GC/MS analysis requires estimating their degradation temperature limits. This limit can be estimated as being equal to the atmospheric pressure boiling point of the highest homologue in the homologous series under consideration that does not decompose on boiling. Copyright
- Kornilova, Tatiana A.,Ukolov, Anton I.,Kostikov, Rafael R.,Zenkevich, Igor G.
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p. 461 - 466
(2013/03/14)
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- Stability of diazocarbonyl compounds under the conditions of gas chromatography and chromatography-mass spectrometry analysis
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The gas chromatographic analysis of alkyldiazoacetates N 2CHCO2R (R = CH3 - C4H9), α-aliphatic diazoketones RCOCHN2 (R = C3H 7, C5H11, and C9H19), and aryl-substituted diazoketones Ph (CH2)nCOCHN2 (n = 0-2) is shown to be possible when their retention temperatures are below the boiling points of compounds of this series at atmospheric pressure without decomposition (about 140°C). At higher temperatures occurs partial or complete decomposition of α-diazoketones in chromatographic columns to form ketenes. Among the impurities in the reaction mixtures at the diazotization of corresponding alkyl glycinates were identified for the first time the nitrate esters of glycolic acid O2NOCH2CO2R, as well as the dimeric products. All diazocarbonyl compounds and the impurities were characterized by mass spectra. For the first time their gas chromatographic retention indices were determined. Pleiades Publishing, Ltd., 2012.
- Kornilova,Ukolov,Kostikov,Zenkevich
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p. 1675 - 1685
(2013/02/23)
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- NOVEL MACROCYLES AND METHODS FOR THEIR PRODUCTION
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There are provided compounds of formula (I) or a pharmaceutically acceptable salt thereof: wherein the variables R1-R3 are as described in the description, said compounds being useful as anti-inflammatory agents with reduced systemic effects.
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Page/Page column 47
(2011/05/05)
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- Highly chemo- and stereoselective intermolecular coupling of diazoacetates to give cis-olefins by using Grubbs second-generation catalyst
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Highly stereoselective formation of cis-2-ene-1,4-diesters by homo- and heterocoupling of α-diazoacetates in the presence of Grubbs second-generation catalyst is demonstrated. The dual reactivity of the catalyst in alkene metathesis and diazocoupling has been exploited in the synthesis of 12-26-membered macrocyclic dienyl dilactones by one-pot carbene dimerisation/ring-closing metathesis.
- Hodgson, David M.,Angrish, Deepshikha
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p. 3470 - 3479
(2008/02/08)
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- Rhodium-mediated stereoselective polymerization of "carbenes"
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Unprecedented rhodium-catalyzed stereoselective polymerization of "carbenes" from ethyl diazoacetate (EDA) to give high molecular mass poly(ethyl 2-ylidene-acetate) is described. The mononuclear, neutral [(N,O-ligand)M1(cod)] (M = Rh, Ir) catalytic precursors for this reaction are characterized by (among others) single-crystal X-ray diffraction. These species mediate formation of a new type of polymers from EDA: carbon-chain polymers functionalized with a polar substituent at each carbon of the polymer backbone. The polymers are obtained as white powders with surprisingly sharp NMR resonances. Solution and solid state NMR data for these new polymers reveal a highly stereoregular polymer, with a high degree of crystallinity. The polymer is likely syndiotactic. Material properties are very different from those of atactic poly(diethyl fumarate) polymer obtained by radical polymerization of diethyl fumarate. Other diazoacetates are also polymerized. Further studies are underway to reveal possible applications of these new materials.
- Hetterscheid, Dennis G. H.,Hendriksen, Coen,Dzik, Wojciech I.,Smits, Jan M. M.,Van Eck, Ernst R. H.,Rowan, Alan E.,Busico, Vincenzo,Vacatello, Michele,Van Axel Castelli, Valeria,Segre, Annalaura,Jellema, Erica,Bloemberg, Tom G.,De Bruin, Bas
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p. 9746 - 9752
(2007/10/03)
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- Intramolecular regioselective insertion into unactivated prochiral carbon-hydrogen bonds with diazoacetates of primary alcohols catalyzed by chiral dirhodium(II) carboxamidates. Highly enantioselective total synthesis of natural lignan lactones
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Intramolecular insertion into unactivated prochiral C-H bonds of 3-aryl-1-propyl diazoacetates catalyzed by dirhodium(II) tetrakis[methyl 1-(3-phenyl propanoyl)imidazolidin-2-one-4(R or S)-carboxylate], Rh2(4R-MPPIM)4 or Rh2(4S-MPPIM)4, occurs in 91-96% ee and with virtually complete regiocontrol for the formation of β-benzyl-γ-butyrolactones. This methodology has been applied to the total synthesis of dibenzylbutyrolactone lignans (-)- and (+)-enterolactone, (-)- and (+)-hinokinin, and (+)-arctigenin from substituted cinnamic acids in 19-27% overall yields. Aryltetralin lignan (+)-isodeoxypodophyllotoxin was prepared from the reactant 3,4-(methylenedioxy)cinnamic acid in 36% yield overall, and the lactone precursor to (+)-isolauricerisinol was formed in 96.5% ee and 23% yield overall. Applications of the chiral Rh2(MPPIM)4 catalysts to fully aliphatic systems resulting in the formation of β-substituted-γ-butyrolactones with high regiocontrol and with 93-96% ee have demonstrated the generality of this methodology. A model that provides accurate predictions of β-substituted-γ-butyrolactone absolute configurations in these asymmetric metal carbene transformations is described.
- Bode,Doyle,Protopopova,Zhou
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p. 9146 - 9155
(2007/10/03)
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- INVESTIGATION OF THE STAUDINGER REACTION BETWEEN BICYCLIC PHOSPHITE AND DIAZO COMPOUNDS
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Nine bicyclic phosphatazines were synthesized by the Staudinger reaction between bicyclic phosphite (1) and diazo compounds (2-5), the Elemental Analysis data, IR, 31P NMR and Mass Spectral data of these compounds are reported.The reaction of diazoacetate with bicyclic phosphite was followed by 31P NMR, the concentration-time curve was simulated by Optimal Approximation with a computer.It was found that this reaction consisted of two steps, the first step was second-order and the second was first-order.A possible mechanism is also proposed.Key words: Staudingerreaction; bicyclic phosphite; phosphatazine; optimal approximation; NMR; IR.
- Pei, Chengxin,Xu, Xuanlong
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p. 143 - 148
(2007/10/02)
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