- Association and Dissociation of Grignard Reagents RMgCl and Their Turbo Variant RMgC?LiCl
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Grignard reagents RMgCl and their so-called turbo variant, the highly reactive RMgC?LiCl, are of exceptional synthetic utility. Nevertheless, it is still not fully understood which species these compounds form in solution and, in particular, in which way LiCl exerts its reactivity-enhancing effect. A combination of electrospray-ionization mass spectrometry, electrical conductivity measurements, NMR spectroscopy (including diffusion-ordered spectroscopy), and quantum chemical calculations is used to analyze solutions of RMgCl (R=Me, Et, Bu, Hex, Oct, Dec, iPr, tBu, Ph) in tetrahydrofuran and other ethereal solvents in the absence and presence of stoichiometric amounts of LiCl. In tetrahydrofuran, RMgCl forms mononuclear species, which are converted into trinuclear anions as a result of the concentration increase experienced during the electrospray process. These trinuclear anions are theoretically predicted to adopt open cubic geometries, which remarkably resemble structural motifs previously found in the solid state. The molecular constituents of RMgCl and RMgC?LiCl are interrelated via Schlenk equilibria and fast intermolecular exchange processes. A small portion of the Grignard reagent also forms anionic ate complexes in solution. The abundance of these more electron-rich and hence supposedly more nucleophilic ate complexes strongly increases upon the addition of LiCl, thus rationalizing its beneficial effect on the reactivity of Grignard reagents.
- Schnegelsberg, Christoph,Bachmann, Sebastian,Kolter, Marlene,Auth, Thomas,John, Michael,Stalke, Dietmar,Koszinowski, Konrad
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supporting information
p. 7752 - 7762
(2016/06/08)
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- COMPLEXES OF IMIDAZOLE LIGANDS
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Metal imidazolate complexes are described where imidazoles ligands functionalized with bulky groups and their anionic counterpart, i.e., imidazolates are described. Compounds comprising one or more such polyalkylated imidazolate anions coordinated to a metal or more than one metal, selected from the group consisting of alkali metals, transition metals, lanthanide metals, actinide metals, main group metals, including the chalcogenides, are contemplated. Alternatively, multiple different imidazole anions, in addition to other different anions, can be coordinated to metals to make new complexes. The synthesis of novel compounds and their use to form thin metal containing films is also contemplated.
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Page/Page column 81
(2012/01/05)
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- AN IMPROVED PROCESS FOR THE PREPARATION OF MORPHINANE ANALOGUES
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The present invention relates to an improved process for preparing morphinane analogues of formula (1) wherein the substituents R1, R2, R2a, R3, R4, R5 and Y have the meanings as defined in the specifications.
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Page/Page column 28
(2009/10/30)
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- METHOD OF MANUFACTURING AN AMINOARYL-CONTAINING ORGANOSILICON COMPOUND AND METHOD OF MANUFACTURING AN INTERMEDIATE PRODUCT OF THE AFOREMENTIONED COMPOUND
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To provide an aminoaryl-containing organosilicon compound with high efficiency, after protecting amino groups of a haloaniline compound with a specific compound, to form a Grignard reagent and to deprotect the aforementioned groups by reacting the Grignard reagent with a silicon compound.
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Page/Page column 17
(2008/06/13)
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- Production processes for triorganomonoalkoxysilanes and triorganomonochlorosilanes
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A silane containing a bulky hydrocarbon group or groups R therein and having the formula (III) [in-line-formulae]R3-(x+y)(R1)x(R2)ySi(OR3) [/in-line-formulae] can be produced by reacting a silane of the formula (I) [in-line-formulae](R1)x(R2) ySiCl3-(x+y)(OR3) [/in-line-formulae] with a Grignard reagent of the formula (II) [in-line-formulae]RMgX [/in-line-formulae] Further, a tri-organo-chlorosilane of the formula (XIIa) [in-line-formulae](R1)(R2)(R3)SiCl [/in-line-formulae] can be produced by reacting a tri-organo-silane of the formula (XIa) [in-line-formulae](R1)(R2)(R3)SiZ1 [/in-line-formulae] with hydrochloric acid. Furthermore, a tri-organo-monoalkoxysilane of the formula (XXIII) [in-line-formulae]R3-(x+y)(R1)x(R2)ySi(OR3) [/in-line-formulae] can be produced when a silane of the formula (XXI) [in-line-formulae](R1)x(R2)ySiCl4-(x+y) [/in-line-formulae] is reacted with a Grignard reagent of the formula (XXII) [in-line-formulae]RMgX [/in-line-formulae] with addition of and reaction with an alcohol or an epoxy compound during the reaction.
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Page/Page column 24
(2008/06/13)
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- Sterically crowded diphosphinomethane ligands: Molecular structures, UV-photoelectron spectroscopy and a convenient general synthesis of tBu2PCH2PtBu2 and related species
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A series of highly crowded symmetric and unsymmetric diphosphinomethanes R2PCH2PR′2, important ligands in transition metal chemistry and catalysis, namely tBu2PCH2ptBu2 (dtbpm, 11), Cy2PCH2PCy2 (dcpm, 2), tBu2PCH2PCy2 (ctbpm, 3), tBu2PCH2PiPr2 (iptbpm, 4) and tBu2PCH2PPh2 (ptbpm, 5), has been prepared in high yields, using a general and convenient route, which is described in detail for 1. Other than 4, which is a colourless liquid, these compounds are crystalline solids at room temperature. Their molecular structures have been determined by single crystal X-ray diffraction, along with that of the higher homologue of 1, tBu2CH2CH2tBu 2 (dtbpe, 6). The solid-state structures of the dioxide of 1, tBu2P(O)CH2P(O)tBu2 (7), and of two phosphonium cations derived from 1, protonated [tBu2P(H)CH2PtBu2] + (8+) and the chlorophosphonium ion [tBu2P(Cl)CH2PtBu2] + (9+), are also described and show a distinct structural influence of the tetracoordinate P centres. The gas phase UV-photoelectron spectra of the diphosphines 1-6 have been measured. Their first two ionisation potentials are found to be nearly degenerate and all are in the low energy range from 7.5 to 7.8 eV. Comparison with related mono- and bidentate phosphines demonstrates that 1-6 are excellent σ-donors towards metals, in accord with their known coordination chemistry. Molecular geometries and electronic structures of the diphosphine systems have been studied by quantum chemical calculations and are compared to experiment. Unlike standard semiempirical methods (AM1, PM3, MNDO), which give rather poor minimum structures and seem inadequate for such sterically crowded systems, ab initio calculations (RHF/6-31G**) predict molecular geometries with reasonable accuracy and reflect the observed trends in experimental ionisation potentials.
- Eisentraeger, Frank,Goethlich, Alexander,Gruber, Irene,Heiss, Helmut,Kiener, Christoph A.,Krueger, Carl,Notheis, J. Ulrich,Rominger, Frank,Scherhag, Gunter,Schultz, Madeleine,Straub, Bernd F.,Volland, Martin A. O.,Hofmann, Peter
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p. 540 - 550
(2007/10/03)
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- Silyl (meth)acrylates having bulky substituent group and preparation thereof
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Silyl (meth)acrylate compounds each having attached to a silicon atom one very bulky tertiary hydrocarbon group and two branched hydrocarbon groups each having a hydrocarbon group at α- or β-position or two cyclic hydrocarbon groups are very stable to hydrolysis and are useful raw materials from which hydrolyzable, self-erodible polymers for ship bottom paints are prepared.
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- Process for the preparation of silanes, with a tertiary hydrocarbon group in the a-position relative to the silicon atom
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The invention relates to a process for the preparation of silanes of the general formula 1 by reaction of Grignard reagents of the general formula 2 with silanes of the general formula 3 wherein R denotes C1 - to C10 -hydrocarbon radicals optionally substituted by fluorine, chlorine or cyano radicals, R1, in the α-position relative to the silicon atom, denotes tertiary C4 - to C30 -hydrocarbon radicals optionally substituted by fluorine, chlorine or cyano radicals, X and X1 each denote chlorine, bromine or iodine, m denotes the values 2 or 3 and n denotes the values 1 or 2, in the presence of a transition metal catalyst and an inert, aprotic, and chelating compound.
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- Method for preparation of tertiary-hydrocarbylsilyl compounds
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A method for the preparation of tertiary-hydrocarbylsilyl compounds. The method comprises contacting a mixture comprising diethylene glycol dibutyl ether, and a Grignard reagent described by formula RMgX with a silicon compound described by formula R1a SiX4-a, where R is a tertiary-hydrocarbyl group comprising four to about 20 carbon atoms, each R1 is an independently selected substituted or unsubstituted monovalent hydrocarbon group comprising one to about 20 carbon atoms, each X is an independently selected halogen atom, and a is an integer with a value of zero to three, in the presence of an effective amount of a copper compound catalyst. The present invention provides a method for making sterically hindered organosilicon intermediates useful in the pharmaceutical industry.
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- Synthesis of deuterium labeled isobutane: Isobutane-2-d1, isobutane-1-d9 and isobutane-d10
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2-Methylpropane-2-d1 (isobutane-2-d1), 2-(methyl-d3)-propane-1,1,1,3,3,3-d6 (nonadeuterated isobutane) and 2-methylpropane-d10 (perdeuterated isobutane) were synthesized by using a combination of classical organic chemistry and recently developed H/D exchange processes on solid acids. Isobutane-2-d1 was synthesized from t-butyl chloride by Grignard synthesis with an overall yield of 27.0% (chemical purity: 99.9% and isotopic purity: 96.0%). Isobutane-1-d9 was prepared by H/D exchange of 2-methylpropane (isobutane) with a D2O exchanged zeolite. The deuteriated product was obtained with an overall yield of 80.0% (chemical purity: 99.9% and isotopic purity: 98.7%). Perdeuteriated isobutane was prepared by reacting isobutane-2-d1 with 98.0% deuteriated sulfuric acid and was obtained in a total yield of 98.0% (chemical purity: 99.8% and isotopic purity: 97.9%).
- Sassi,Coeppert,Sommer,Esteves,Mota
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p. 1023 - 1030
(2007/10/03)
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- Partially solvated alkylmagnesium chlorides in toluene
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Toluene solutions of alkylmagnesium chlorides partially solvated by diethyl ether were investigated. Primary and secondary alkyl chlorides can be converted into Grignard reagents in good yields in the presence of small amounts of ether (less than one mole per mole of halide). Tertiary chlorides form only monosolvated organomagnesium compounds. Ultrasound accelerates the process. The reagents obtained are heterogeneous, but the solubilities of the partially solvated complexes in toluene are fairly high. Some of the reagents disproportionate to magnesium chloride and the dialkylmagnesium. The extent of disproportionation decreases with an increase in the concentration of the reagent or in the steric requirements of the alkyl moiety.
- Tuulmets, Ants,Mikk, Marvi,Panov, Dmitri
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p. 133 - 138
(2007/10/03)
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- Active Magnesium from Catalytically Prepared Magnesium Hydride or from Magnesium Anthracene and its Uses in the Synthesis
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Highly reactive, pyrophoric forms of magnesium with specific surface areas of 20-109 m2/g (Mg*) can be generated by the dehydrogenation of catalytically prepared magnesium hydride (MgH2*) or by decomposition of magnesium anthracene * 3 THF (4).The decomposition of 4, with recovery of anthracene and THF, may be accomplished both thermally and by ultrasound in an organic solvent (toluene, n-heptane) or thermally in the solid state in vacuo.Mg* obtained by the latter method exhibits only weak reflections in the X-ray powder diagram and has, in comparison to other mentioned Mg* species, the highest reactivity toward hydrogen.Diverse Grignard compounds can be prepared under mild conditions (* from MgH2* or 4.The cleavage of THF with formation of 1-oxa-2-magnesiacyclohexane (2) is possible by employing Mg* from NgH2* or 4.
- Bartmann, Ekkehard,Bogdanovic, Borislav,Janke, Nikolaus,Liao, Shijan,Schlichte, Klaus,et al.
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p. 1517 - 1528
(2007/10/02)
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- Use of Magnesium Anthracene * 3 THF in Synthesis: Generation of Grignard Compounds and Other Reactions with Organic Halides
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The course (a), (b), (c) (Scheme 1) of the reaction of magnesium anthracene * 3 THF (1) with organic halides (RX) is dependent on the nature of RX.With alkyl halides in THF 1 reacts as a nucleophile, whereby primary as well as secondary alkyl halides produce dialkyldihydroanthracenes (4-4'') and tertiary alkyl halides yield primarily monoalkyl-substituted dihydroanthracenes (2, 2').With bromo- and iodobenzene in THF 1 reacts predominantly as a radical with H atom abstraction from the solvent affording benzene and 9.The formation of Grignard compounds (5) and anthracene (6), originating from primary and secondary alkyl and aryl halides and 1 in toluene or ether at elevated temperatures, is not caused by the reaction of 1 but by the "active magnesium" (Mg*) formed by decomposition of 1 in these solvents.In contrast, allyl, propargyl, and benzyl halides react with 1 independently of the solvent under mild conditions to produce 5 and 6.Allyl- and the difficultly accessible allenylmagnesium chloride can be prepared in THF at -78 and 0 deg C, respectively, from the corresponding halides and ordinary Mg powder via catalytic amounts of 1.
- Bogdanovic, Borislav,Janke, Nikolaus,Kinzelmann, Hans-Georg
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p. 1507 - 1515
(2007/10/02)
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- Method for the preparation of a tert-hydrocarbyl silyl compound
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A tert-hydrocarbyl, e.g. tert-butyl, silyl compound can be synthesized easily according to the method of the invention in which a tert-hydrocarbylmagnesium halide as a Grignard reagent is reacted with a silane compound having at least one silicon-bonded hydrogen atom and at least one silicon-bonded halogen atom simultaneously in a molecule in a suitable organic solvent so that the halogen atom in the latter reactant is replaced with the tert-hydrocarbyl group in the former reactant to give the desired tert-hydrocarbyl silyl compound in a high yield without the safety problem in the conventional method using a tert-alkyl lithium as the reactant.
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- IRON CATALYZED CROSS-COUPLING REACTIONS OF ACYL CHLORIDES WITH GRIGNARD REAGENTS. A MILD, GENERAL, AND CONVENIENT SYNTHESIS OF ALIPHATIC AND AROMATIC KETONES.
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Acyl chlorides couple with Grignard reagents at room temperature in the presence of catalytic amounts of tris(acetylacetonate)iron(III), Fe(acac)3.The reaction is general with respect to both reactants and provides a very mild and convenient method for the synthesis of aliphatic and aromatic ketones.
- Fiandanese, V.,Marchese, G.,Martina, V.,Ronzini, L.
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p. 4805 - 4808
(2007/10/02)
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