Academic literature on the topic 'Hydride trapping'
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Journal articles on the topic "Hydride trapping"
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Howard, A. G., and S. D. W. Comber. "Hydride-trapping techniques for the speciation of arsenic." Mikrochimica Acta 109, no. 1-4 (January 1992): 27–33. http://dx.doi.org/10.1007/bf01243206.
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Romero, Vanesa, Laura Vilas, Isela Lavilla, and Carlos Bendicho. "Speciation of inorganic As and Sb in natural waters by total reflection X-ray fluorescence following selective hydride generation and trapping onto quartz reflectors coated with nanostructured Pd." Journal of Analytical Atomic Spectrometry 32, no. 9 (2017): 1705–12. http://dx.doi.org/10.1039/c7ja00113d.
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Teichert, Johannes F., and Lea T. Brechmann. "Catch It If You Can: Copper-Catalyzed (Transfer) Hydrogenation Reactions and Coupling Reactions by Intercepting Reactive Intermediates Thereof." Synthesis 52, no. 17 (July 13, 2020): 2483–96. http://dx.doi.org/10.1055/s-0040-1707185.
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The key reactive intermediate of copper(I)-catalyzed alkyne semihydrogenations is a vinylcopper(I) complex. This intermediate can be exploited as a starting point for a variety of trapping reactions. In this manner, an alkyne semihydrogenation can be turned into a dihydrogen-mediated coupling reaction. Therefore, the development of copper-catalyzed (transfer) hydrogenation reactions is closely intertwined with the corresponding reductive trapping reactions. This short review highlights and conceptualizes the results in this area so far, with H2-mediated carbon–carbon and carbon–heteroatom bond-forming reactions emerging under both a transfer hydrogenation setting as well as with the direct use of H2. In all cases, highly selective catalysts are required that give rise to atom-economic multicomponent coupling reactions with rapidly rising molecular complexity. The coupling reactions are put into perspective by presenting the corresponding (transfer) hydrogenation processes first.1 Introduction: H2-Mediated C–C Bond-Forming Reactions2 Accessing Copper(I) Hydride Complexes as Key Reagents for Coupling Reactions; Requirements for Successful Trapping Reactions 3 Homogeneous Copper-Catalyzed Transfer Hydrogenations4 Trapping of Reactive Intermediates of Alkyne Transfer Semihydrogenation Reactions: First Steps Towards Hydrogenative Alkyne Functionalizations 5 Copper(I)-Catalyzed Alkyne Semihydrogenations6 Copper(I)-Catalyzed H2-Mediated Alkyne Functionalizations; Trapping of Reactive Intermediates from Catalytic Hydrogenations6.1 A Detour: Copper(I)-Catalyzed Allylic Reductions, Catalytic Generation of Hydride Nucleophiles from H2 6.2 Trapping with Allylic Electrophiles: A Copper(I)-Catalyzed Hydroallylation Reaction of Alkynes 6.3 Trapping with Aryl Iodides7 Conclusion
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Bönisch, Matthias, Michael Zehetbauer, Maciej Krystian, Daria Setman, and Gerhard Krexner. "Stabilization of Lattice Defects in HPT-Deformed Palladium Hydride." Materials Science Forum 667-669 (December 2010): 427–32. http://dx.doi.org/10.4028/www.scientific.net/msf.667-669.427.
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Recent investigations on palladium hydride (Pd-H) showed, for the first time, evidence of formation of vacancy-hydrogen (Vac-H) clusters during Severe Plastic Deformation (SPD) effected by High Pressure Torsion (HPT). Vacancy concentrations produced in Pd-H by this method are extraordinarily high. DSC-scans show that the thermal stability range of vacancies is extended by about 150K due to trapping of hydrogen leading to the formation of vacancy-hydrogen clusters. Recent experiments give evidence that the mobility of the H atoms and/or the vacancies is conditional for the formation of Vac-H clusters during HPT. Results furthermore indicate defect stabilization by hydrogen trapping not only for vacancy-type defects but also for dislocations and grain boundaries.
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Mohamed, Mustafa, and Michael A. Brook. "Photolysis of tris(trimethylsilyl)silane: trapping of sisyl radicals." Canadian Journal of Chemistry 78, no. 11 (November 1, 2000): 1357–62. http://dx.doi.org/10.1139/v00-085.
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The photolysis of tris(trimethylsilyl)silane (TTMSS) was studied in the absence and in the presence of added trapping agents such as alkenes and alcohols. It was found that, unlike the case with pyrolysis, silyl radicals rather than silylenes are produced. They may be efficiently trapped with alkenes, to give the hydrosilylation products, but not with alcohols. The major product from the photolysis of TTMSS in the absence of added trapping agent (or with alcohols as trapping agents) was tetrakis(trimethylsilyl)silane. Possible mechanisms to account for the photoproducts are presented.Key words: hydrosilane, photolysis, silylenes, silyl radical, sisyl hydride.
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Dočekal, B., J. Dědina, and V. Krivan. "Radiotracer investigation of hydride trapping efficiency within a graphite furnace." Spectrochimica Acta Part B: Atomic Spectroscopy 52, no. 6 (June 1997): 787–94. http://dx.doi.org/10.1016/s0584-8547(96)01605-9.
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Ma, Baoguang, Jens Henrik Hansen, Søren Hvilsted, and Anne Ladegaard Skov. "Control of PDMS crosslinking by encapsulating a hydride crosslinker in a PMMA microcapsule." RSC Adv. 4, no. 88 (2014): 47505–12. http://dx.doi.org/10.1039/c4ra07513g.
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Tsalev, D. L., and P. B. Mandjukov. "Electrothermal atomic absorption spectrophotometric determination of hydride-forming elements after simultaneous preconcentration by hydride generation and trapping hydrides in cerium(iv)-potassium iodide absorbing solution." Microchemical Journal 35, no. 1 (February 1987): 83–93. http://dx.doi.org/10.1016/0026-265x(87)90202-5.
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Alvarez, M., Daniel García-Vivó, Estefanía Huergo, and Miguel Ruiz. "Trapping of an Heterometallic Unsaturated Hydride: Structure and Properties of the Ammonia Complex [MoMnCp(μ-H)(μ-PPh2)(CO)5(NH3)]." Inorganics 6, no. 4 (November 24, 2018): 125. http://dx.doi.org/10.3390/inorganics6040125.
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Complexes displaying multiple bonds between different metal atoms have considerable synthetic potential because of the combination of the high electronic and coordinative unsaturation associated to multiple bonds with the intrinsic polarity of heterometallic bonds but their number is scarce and its chemistry has been relatively little explored. In a preliminary study, our attempted synthesis of the unsaturated hydrides [MoMCp(μ-H)(μ-PR2)(CO)5] from anions [MoMCp(μ-PR2)(CO)5]− and (NH4)PF6 yielded instead the ammonia complexes [MoMCp(μ-H)(μ-PR2)(CO)5(NH3)] (M = Mn, R = Ph; M = Re, R = Cy). We have now examined the structure and behaviour of the MoMn complex (Mo–Mn = 3.087(3) Å) and found that it easily dissociates NH3 (this requiring some 40 kJ/mol, according to DFT calculations), to yield the undetectable unsaturated hydride [MoMnCp(μ-H)(μ-PPh2)(CO)5] (computed Mo–Mn = 2.796 Å), the latter readily adding simple donors L such as CNR (R = Xyl, p-C6H4OMe) and P(OMe)3, to give the corresponding electron-precise derivatives [MoMnCp(μ-H)(μ-PPh2)(CO)5(L)]. Thus the ammonia complex eventually behaves as a synthetic equivalent of the unsaturated hydride [MoMnCp(μ-H)(μ-PPh2)(CO)5]. The isocyanide derivatives retained the stereochemistry of the parent complex (Mo–Mn = 3.0770(4) Å when R = Xyl) but a carbonyl rearrangement takes place in the reaction with phosphite to leave the entering ligand trans to the PPh2 group, a position more favoured on steric grounds.
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Ivanenko, Natalya B., Nikolay D. Solovyev, Anatoly A. Ivanenko, and Denis V. Navolotskii. "Biological monitoring of arsenic pollution based on whole blood arsenic atomic absorption assessment with in situ hydride trapping." J. Anal. At. Spectrom. 29, no. 10 (2014): 1850–57. http://dx.doi.org/10.1039/c4ja00130c.
Full textDissertations / Theses on the topic "Hydride trapping"
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Menemenlioglu, Ipek. "Electrochemical Hydride Generation And Atom Trapping Atomic Absorption Spectrometry For Determination Of Antimony." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605018/index.pdf.
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ABSTRACT
ELECTROCHEMICAL HYDRIDE GENERATION AND ATOM TRAPPING ATOMIC ABSORPTION SPECTROMETRY FOR DETERMINATION OF ANTIMONY
Menemenlioglu, ipek
M.S., Department of Chemistry
Supervisor: Prof. Dr. O. Yavuz Ataman
June 2004, 82 pages
Electrochemical hydride generation is a suitable alternative to common hydride generation by NaBH4 which is widely used for the detection of volatile elements such as As, Se, Sb, Sn, Bi, Ge, Te and Pb. In this study, a thin-layer flow through electrochemical cell was designed. Lead and platinum foils were employed as cathode and anode materials, respectively, for the generation of antimony hydride. Argon was used as the carrier gas. The inlet arm of the conventional quartz tube atomizer was used for on-line preconcentration of generated hydrides. A portion of the inlet arm was heated externally to the collection temperature for trapping the analyte species which were generated electrochemically. For the revolatilization of the trapped species, the trap was further heated to the revolatilization temperature and hydrogen gas was introduced into the system 10 seconds afterwards. The experimental operation conditions for electrochemical hydride generation which include the acidities and flow rates of catholyte and anolyte solutions, carrier gas flow rate and the applied electric current, were optimized. For trapping, collection and revolatilization temperatures and hydrogen flow rates were optimized. Analyses of standard reference materials were performed to check the accuracy of the proposed method. 3σ
limit of detections were found as 1.03 ng ml-1 and 0.053 ng ml-1 with and without employing the trap, respectively. The trap has provided 20 fold sensitivity improvement.
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Yildirim, Emrah. "Tellurium Speciation Using Hydride Generation Atomic Absorption Spectrometry And In-situ Graphite Cuvette Trapping." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/3/12610967/index.pdf.
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In recent years speciation analysis is becoming more important as it is known that each chemical form of an element behaves differently in biological and environmental media. Since abundance of tellurium in earth crust is extremely low, very sensitive and accurate methods are needed to determine the concentration of tellurium. Hydride generation atomic absorption is a sensitive, fast and economical technique applied for the determination of tellurium. Speciation of tellurium can be achieved by making use of different kinetic behaviors of Te(IV) and Te(VI) upon its reaction with sodiumborohydride.
A continuous flow hydride generation system was developed and parameters that affect the analytical signal were optimized. Sample solutions were prepared in 4.0 mol/L HClas reductant 0.5 % (w/v) sodiumborohydride in 0.5 % (w/v) NaOH was used. Quantitative reduction of Te(VI) was achieved through application of a microwave assisted prereduction of Te(VI) in 6.0 mol/L HCl solution. Sensitivity of the system was further enhanced by in-situ trapping of the formed H2Te species in a previously heated graphite furnace whose surface was modified using Pd or Ru. Overall efficiency of pyrolytic coated graphite surface was found to be 15% when hydrides are trapped for 60 seconds at 300 oC. LOD and LOQ values were calculated as 86 pg/mL and 287 pg/mL according to peak height values. Efficiency was increased by 46% and 36% when Pd and Ru modifiers were used, respectively. With Ru modified graphite tube 173 fold enhancement was obtained over 180 seconds trapping period with respect to direct ETAAS. LOD values were 6.4 and 2.2 pg/mL for Pd and Ru treated systems, respectively, for 180 s collection of 9.6 mL sample solution.
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Akay, Pinar. "Inorganic Antimony Speciation Using Tungsten Coil Atom Trap And Hydride Generation Atomic Absorption Spectrometry." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/3/12611543/index.pdf.
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Antimony is a toxic element which is mostly found in two oxidation states (III and V) in environmental, biological and geological samples. Antimony may form various inorganic and organic compounds that exhibit differences in analytical behavior, toxicity and mobilityinorganic compounds of antimony are more toxic than organic forms and toxicity of Sb(III) has been shown to be 10 times higher than that of Sb(V). Therefore selective determination of Sb(III) and Sb(V) is required in environmental and biological samples. Hydride generation atomic absorption spectrometry is a sensitive, fast and economical technique for the determination of antimony at trace level. A possible non-chromatographic method for antimony speciation is hydride generation atomic absorption spectrometry that is based on the relatively slow kinetics of hydride formation from Sb(V). In this study, continuous flow hydride generation method for the determination of antimony was developed and hydride generation conditions were optimized. Analyte solution was prepared in 0.050 mol/L HCl and 1.2% (w/v) NaBH4 stabilized in 0.30% (w/v) NaOH was used as a reductant solution. Inorganic antimony speciation conditions were determined by continuous flow HGAAS system. For the pre-reduction of Sb(V) to Sb(III), 8.0% (w/v) potassium iodide (KI) and 0.10% (w/v) ascorbic acid were used. Further speciation study was also carried out using Ir coated W-coil Atom Trap Hydride Generation Atomic Absorption Spectrometry. Tungsten coil atom trap was used to enhance the sensitivity. Tungsten coil surface was treated with Ir and totally 250 &
#956
g 1000 mg/L Ir stock solution was used for coating of tungsten coil. LOD and LOQ values were calculated as 152 pg/mL and 508 pg/mL according to 120 seconds trapping. 128 and 37 fold enhancement were obtained for 120 seconds collection with respect to W-coil-ETAAS and ETAAS, respectively.
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Furdíková, Zuzana. "Studium generování, záchytu a atomizace těkavých hydridů pro metody atomové spektrometrie." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2009. http://www.nusl.cz/ntk/nusl-233290.
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Interference effects of co-generated hydrides of arsenic, antimony, bismuth and selenium on trapping behavior of selenium or antimony hydrides (analytes) within iridium modified, transversely heated graphite tube atomizer (THGA) was investigated. A twin-channel hydride generation system was used for independent separate generation and introduction of analyte and interferent hydrides, i.e. in simultaneous and/or sequential analyte-interferent and interferent-analyte mode of operation. Influence of the analyte and modifier mass, interferent amount, trapping temperature and composition of the gaseous phase was studied. A simple approach for elimination of mutual interference effects by modification of the gaseous phase with oxygen in substoichiometric ratio to chemically generated hydrogen is proposed and suppression of these interference effects is demonstrated. A hypothesis on mechanism of trapping and mutual interference effects is drawn.
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Krejčí, Pavel. "Studium miniaturních zařízení pro kolekci hydridotvorných prvků v atomové spektroskopii." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2011. http://www.nusl.cz/ntk/nusl-233325.
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Capability of a prototype of miniature collection device based on a strip of the molybdenum foil for collecting hydride forming elements (As, Se, Sb and Bi) was studied. The device was combined with a miniature hydrogen diffusion flame for detection by atomic absorption spectrometry. The conditions for trapping and subsequent vaporization of analytes of interest were optimized. A twin-channel hydride generation system was used for study of mutual interference effects of co-generated hydride forming elements. The influence of modification of the molybdenum surface with noble metals - Rh, Pt and Ir on trapping and vaporization processes was also studied and changes of microstructure of the foil surface after modification were investigated using scanning electron microscope equipped with energy dispersive x-ray analyzer and electron backscattered diffraction system. Complementary radiotracer and radiography experiments were performed in order to determine trapping efficiency and to assess the spatial distribution of collected analytes within the device. Practical application of the method was demonstrated on determination of antimony in water samples at trace level. Possibility of multi-element analysis was demonstrated by combining the collection device with atomization and excitation of the analyte in microwave induced plasma and with detection by atomic emission spectrometry method. The results of the experiments proved that tested miniature collection device is capable of trapping analytes that form volatile hydrides. This device can be coupled to various types of atomizers, typically used in spectrometry methods. Thus, very sensitive and specific detection of hydride forming elements can be performed.
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Duben, Ondřej. "Stanovení selenu metodou HG-AAS s prekoncentrací a atomizací v plazmovém výboji s dielektrickou bariérou." Master's thesis, 2015. http://www.nusl.cz/ntk/nusl-342936.
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The aim of this thesis was to optimize atomization conditions for selenium hydride in a novel plasma atomizer based on dielectric barrier discharge (DBD) using atomic absorption spectrometry as a detector. Analytical characteristics have been subsequently determined and compared to those reached in a conventional externally heated quartz tube atomizer which was replaced by a sofisticated design of a multiatomizer (MMQTA) in this work. The limit of detection reached in DBD (0,24 ng ml−1 Se) is slightly worse to that observed in MMQTA (0,15 ng ml−1 Se). On the contrary, slightly better resistance towards interferences of Sb, Bi and As was observed in DBD atomizer in comparison with MMQTA. Possibility of selenium preconcentration in a DBD atomizer was studied reaching an overall preconcentration efficiency of 75 ± 5%. The detection limit in a preconcentration mode employing preconcentration period of 300 s has reached 0,012 ng ml−1 Se. Key words: hydride generation atomic absorption spectrometry, dielectric barrier discharge, hydride atomization, hydride trapping, selenium
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Svoboda, Milan. "Studium generování hydridů pro účely speciační analýzy arsenu spojené s AAS a AFS detekcí." Doctoral thesis, 2012. http://www.nusl.cz/ntk/nusl-330387.
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The general aim of this work was a development of methodology and instrumentation for speciation analysis based on the combination of the selective generation of substituted hydrides with atomic absorption or atomic fluorescence spectrometry detection. The first topic of this work was the development of methodology and instrumentation for arsenic speciation analysis based on selective generation of substituted arsines with trapping in the cryogenic trap (U-tube packed with chromosorb) with AAS detection (HG- CT-AAS). The conditions of the selective hydride generation approach as well as working procedure of the cryogenic trap were optimized (appropriate approach for hydride generation, set up of heating program of cryogenic trap, new dryer - cartidge with NaOH, elimination of unspecific absorption, decreasing of the detection limits). The second important part of the work lay in applying of the developed method for arsenic speciation analysis in a homogenized mouse liver tissue. The direct slurry sampling to hydride generator was develop. Moreover the information about oxidation state (iAsIII,V , MAsIII,V a DMAsIII,V ) was obtain. The effect of relevant experimental parameters such as tetrahydroborate concentration, TRIS buffer concentration and time of pre-reduction of the samples by L-cysteine...
Book chapters on the topic "Hydride trapping"
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Taber, Douglass F. "The Li/Yang Synthesis of (±)-Maoecrystal V." In Organic Synthesis. Oxford University Press, 2013. http://dx.doi.org/10.1093/oso/9780199965724.003.0100.
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Maoecrystal V 3, isolated from the Chinese medicinal herb Isodon eriocalyx, shows selective inhibition of HeLa cells at low nanomolar concentration (IC50 = 60 nm). Chuang-Chuang Li of Shenzen Graduate School of Peking University and Zhen Yang of Peking University, Beijing, designed (J. Am. Chem. Soc. 2010, 132, 16745) the first total synthesis of 3, based on the intramolecular Diels-Alder cyclization of 1 to 2. The preparation of 1 began with the ketone 4. Methoxycarbonylation of 4 followed by with high diastereocontrol to coupling with 6 delivered 7. As expected, hydride reduction of the cyclic β-keto ester proceeded give the undesired trans diastereomer. Fortunately, the bulky tetrabuylammonium borohydride delivered the cis diastereomer, which could be reduced to the diol 8. Rh-catalyzed carbene insertion into the O-H bond followed by condensation with formaldehyde then completed the preparation of the precursor 10. Deprotection of 10 followed by oxidation presumably gave 1. There are two faces to the diene of 1, and then the acetoxylated stereogenic center, so four products are possible. In the event, three of the four were observed, of which 2 was the major. To complete the synthesis of 3, the secondary alcohol of 11 was introduced by allylic bromination followed by radical reduction and trapping with TEMPO. The acetoxy group was reduced off, and then the more reactive alkene was removed by selective hydrogenation. Oxidation and base treatment then delivered the equilibrium mixture of (±)-maoecrystal V 3 and its methyl epimer. The synthesis of 3 as reported led to the racemate of the natural product. The starting cyclohexene 1 can be prepared (Tetrahedron Lett . 2000, 41, 3871) from 2,2-dimethylcyclohexane- 1,3-dione 12. Yeast reduction of the prochiral 12 is known to proceed with high (S)-induction. It may be that a route could be devised from the reduction product 13 to enantiomerically pure 7.
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Taber, Douglass. "The Wood Synthesis of Welwitindolinone A Isonitrile." In Organic Synthesis. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199764549.003.0095.
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Welwitindolinone A Isonitrile 3 is the first of a family of oxindole natural products isolated from the cyanobacteria Hapalosiphon welwischii and Westiella intricate on the basis of their activity for reversing multiple drug resistance (MDR). A key transformation in the total synthesis of 3 reported (J. Am. Chem. Soc. 2008, 130, 2087) by John L. Wood, now at Colorado State University, was the chlorination of 1, that in one step established both the axial secondary chloro substituent and the flanking chiral quaternary center. The starting material for the synthesis of 3 was the diene acetonide 5, readily prepared from the Birch reduction product 4. Intermolecular ketene cycloaddition proceeded with high regio- and diastereoselectivity, to give the bicyclooctenone 6. The triazene-bearing Grignard reagent 7 added to the ketone 6 with the anticipated high diastereocontrol, to give, after reduction and protection, the cyclic urethane 8. Selective oxidation of the diol derived from 8 followed by silylation delivered the enone 9. Conjugate addition of hydride followed by enolate trapping gave the trifl ate 10. Pd-catalyzed meth-oxycarbonylation established the methyl ester 11. Addition of CH3MgBr to 11 gave 1, setting the stage for the establishment of the two key stereogenic centers of 2 and so of 3. The transformation of 1 to 2 was envisioned as being initiated by formation of a bridging chloronium ion. Pinacol-like 1,2-methyl migration then proceeded to form the trans diaxial product, moving the ketone-bearing branch equatorial. In addition to being an elegant solution of the problem of how to establish the axial chloro substituent of 3, this strategy might have some generality for the stereocontrolled construction of other alkylated cyclic quaternary centers. Reduction of the ketone 2 and dehydration of the resulting alcohol led, after deprotection and oxidation, to the ketone 12. Protection followed by β-elimination gave the enone 13. Direct reductive amination of 13 failed, but reduction of the methoxime was successful, giving, after acylation, the formamide 14. Reductive N-O bond cleavage followed by deprotection and isonitrile formation then set the stage for the planned intramolecular acylation to complete the synthesis of Welwitindolinone A Isonitrile 3.
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Taber, Douglass F. "Metal-Mediated Carbocyclic Construction: The Whitby Synthesis of (+)-Mucosin." In Organic Synthesis. Oxford University Press, 2015. http://dx.doi.org/10.1093/oso/9780190200794.003.0075.
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Erick M. Carreira of ETH-Zürich generated (Org. Lett. 2012, 14, 2162) ethyl diazoacetate in situ in the presence of the alkene 1 and an iron catalyst to give the cyclopropane 3. Joseph M. Fox of the University of Delaware inserted (Chem. Sci. 2012, 3, 1589) the Rh carbene derived from 5 into the alkene 4 to give the cyclopropene 6, without β-hydride elimination. Masaatsu Adachi and Toshio Nishikawa of Nagoya University reduced (Chem. Lett. 2012, 41, 287) the enone 7 to give the cyclobutanol 8. Intramolecular ketene cycloaddition has been limited to very electron-rich acceptor alkenes. Xiao-Ping Cao and Yong-Qiang Tu of Lanzhou University devised (Chem. Sci. 2012, 3, 1975) a protocol that converted 9 into the cyclobutanone 10 with high diastereocontrol. The intermediate is the tosylhydrazone of the ketone, so a reductive workup would lead to the corresponding cycloalkane. Koichi Mikami of the Tokyo Institute of Technology added (J. Am. Chem. Soc. 2012, 134, 10329) alkyl cuprates to the prochiral enone 11 to give the enolate trapping product 13 in high ee and with high diastereocontrol. Marcus A. Tius of the University of Hawaii found (Angew. Chem. Int. Ed. 2012, 51, 5727) a Pd catalyst for the Nazarov cyclization of 14 to 15. Antoni Riera and Xavier Verdaguer of the Universitat de Barcelona prepared (Org. Lett. 2012, 14, 3534) 16 by enantioselective Pauson-Khand addition to tetramethyl norbornadiene. Conjugate addition followed by retro Diels-Alder could potentially lead to the cyclopentenone 17. The intermolecular Pauson-Khand cyclization often gives mixtures of regioisomers. José Barluenga of the Universidad de Oviedo demonstrated (Angew. Chem. Int. Ed. 2012, 51, 183) an alternative, the addition of an alkenyl lithium 19 to the Fischer carbene 18 leading to 20. Jian-Hua Xie and Qi-Lin Zhou of Nankai University hydrogenated (Adv. Synth. Catal. 2012, 354, 1105; see also Org. Lett. 2012, 14, 2714) the ketone 21 under epimerizing conditions to give the alcohol 22. Kozo Shishido of the University of Tokushima observed (Tetrahedron Lett. 2012, 53, 145) that the intramolecular Heck cyclization of 23 proceeded with high diastereocontrol. Zhi-Xiang Yu of Peking University devised (Org. Lett. 2012, 14, 692) an Rh catalyst for the cyclocarbonylation of 25 to 26.
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Taber, Douglass. "Functionalization of C-H Bonds: The Baran Synthesis of Dihydroxyeudesmane." In Organic Synthesis. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199764549.003.0016.
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Arumugam Sudalai of the National Chemical Laboratory, Pune reported (Tetrahedron Lett. 2008, 49, 6401) a procedure for hydrocarbon iodination. With straight chain hydrocarbons, only secondary iodination was observed. Chao-Jun Li of McGill University uncovered (Adv. Synth. Cat. 2009, 351, 353) a procedure for direct hydrocarbon amination, converting cyclohexane 1 into the amine 3. Justin Du Bois of Stanford University established (Angew. Chem. Int. Ed. 2009, 48, 4513) a procedure for alkane hydroxylation, converting 4 selectively into the alcohol 6. The oxirane 8 usually also preferentially ozidizes methines, hydroxylating steroids at the C-14 position. Ruggero Curci of the University of Bari found (Tetrahedron Lett. 2008, 49, 5614) that the substrate 7 showed some C-14 hydroxylation, but also a useful yield of the ketone 9. The authors suggested that the C-7 acetoxy group may be deactivating the C-14 C-H. C-H bonds can also be converted directly to carbon-carbon bonds. Mark E. Wood of the University of Exeter found (Tetrahedron Lett. 2009, 50, 3400) that free-radical removal of iodine from 10 followed by intramolecular H-atom abstraction in the presence of the trapping agent 11 delivered 12 with good diastereo control. Professor Li observed (Angew. Chem. Int. Ed. 2008, 47, 6278) that under Ru catalysis, hydrocarbons such as 13 could be directly arylated. He also established (Tetrahedron Lett. 2008, 49, 5601) conditions for the direct aminoalkylation of hydrocarbons such as 13, to give 17. Huw M. L. Davies of Emory University converted (Synlett 2009, 151) the ester 4 to the homologated diester 19 in preparatively useful yield using the diazo ester 18, the precursor to a selective, push-pull stabilized carbene. Intramolecular bond formation to an unactivated C-H can be even more selective. Guoshen Liu of the Shanghai Institute of Organic Chemistry developed (Organic Lett. 2009, 11, 2707) an oxidative Pd system that cyclized 20 to the seven-membered ring lactam 21 . Professor Du Bois devised (J. Am. Chem. Soc. 2008 , 130, 9220) a Rh catalyst that effected allylic amination of 22, to give 23 with substantial enantiocontrol. Dalibor Sames of Columbia University designed (J. Am. Chem. Soc. 2009, 131, 402) a remarkable cascade approach to C-H functionalization. Exposure of 24 to Lewis acid led to intramolecular hydride abstraction. Cyclization of the resulting stabilized carbocation delivered the tetrahydropyan 25 with remarkable diastereocontrol.
Conference papers on the topic "Hydride trapping"
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Kim, Hak-Sung, and Gye-Chun Cho. "Experimental Simulation of Self-Trapping Mechanism of CO2 Hydrates in Marine Sediments." In ASME 2016 35th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/omae2016-54213.
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CO2 hydrate-bearing sediments imply that the formation of CO2 hydrates in unconsolidated sediments decreases permeability and increases the stiffness of the sediment system significantly. Therefore, CO2 hydrate-bearing sediments act as cap-rocks which prevent the CO2 leakage from CO2-stored layer. In this study, an experimental simulation of CO2 geological storage into marine unconsolidated sediments was performed. CO2 hydrates were formed during CO2 liquid injection process, resulting in prevention of CO2 upward flow. Temperature, pressure, P-wave velocity, and electrical resistance were measured during the experiment, and their measurement results verify the occurrence of self-trapping effect induced by CO2 hydrate formation.
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Kumar, Sanjay. "Internal structure of hydrated sediments and BSR as seismic evidence of free gas trapping by hydrate zone." In Offshore Technology Conference. Offshore Technology Conference, 1998. http://dx.doi.org/10.4043/8683-ms.
Full textReports on the topic "Hydride trapping"
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Foiles, Stephen M., and Corbett Chandler Battaile. Helium trapping at erbium oxide precipitates in erbium hydride. Office of Scientific and Technical Information (OSTI), February 2016. http://dx.doi.org/10.2172/1237521.
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Trowbridge, L. D. Molten Hydroxide Trapping Process for Radioiodine. Office of Scientific and Technical Information (OSTI), January 2003. http://dx.doi.org/10.2172/885865.
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