- A General and Selective Synthesis of Methylmonochlorosilanes from Di-, Tri-, and Tetrachlorosilanes
-
Direct catalytic transformation of chlorosilanes into organosilicon compounds remains challenging due to difficulty in cleaving the strong Si-Cl bond(s). We herein report the palladium-catalyzed cross-coupling reaction of chlorosilanes with organoaluminum reagents. A combination of [Pd(C3H5)Cl]2 and DavePhos ligand catalyzed the selective methylation of various dichlorosilanes 1, trichlorosilanes 5, and tetrachlorosilane 6 to give the corresponding monochlorosilanes.
- Naganawa, Yuki,Nakajima, Yumiko,Sakamoto, Kei
-
supporting information
p. 601 - 606
(2021/01/13)
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- METHOD FOR PRODUCING ARYLSILANE COMPOUND CONTAINING HALOSILANE COMPOUND AS RAW MATERIAL
-
PROBLEM TO BE SOLVED: To provide a method for producing an arylsilane compound with low production cost. SOLUTION: A method for producing an arylsilane compound includes a reaction step for the cross-coupling reaction of a halosilane compound represented by general formula (A-1), (A-2), or (A-3) and an arylboronic acid pinacol ester in the presence of a nickel catalyst, a Lewis acid catalyst, and an organic base (R independently represent an aromatic hydrocarbon group, a heteroaromatic ring group, or a C1-20 hydrocarbon group; X independently represent a halogeno group or a trifluoromethanesulfonyloxy group). SELECTED DRAWING: None COPYRIGHT: (C)2020,JPOandINPIT
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-
Paragraph 0073-0077
(2020/03/06)
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- Neutral-Eosin-Y-Photocatalyzed Silane Chlorination Using Dichloromethane
-
Chlorosilanes are versatile reagents in organic synthesis and material science. A mild pathway is now reported for the quantitative conversion of hydrosilanes to silyl chlorides under visible-light irradiation using neutral eosin Y as a hydrogen-atom-transfer photocatalyst and dichloromethane as a chlorinating agent. Stepwise chlorination of di- and trihydrosilanes was achieved in a highly selective fashion assisted by continuous-flow micro-tubing reactors. The ability to access silyl radicals using photocatalytic Si?H activation promoted by eosin Y offers new perspectives for the synthesis of valuable silicon reagents in a convenient and green manner.
- Fan, Xuanzi,Xiao, Pin,Jiao, Zeqing,Yang, Tingting,Dai, Xiaojuan,Xu, Wengang,Tan, Jin Da,Cui, Ganglong,Su, Hongmei,Fang, Weihai,Wu, Jie
-
supporting information
p. 12580 - 12584
(2019/08/16)
-
- METHOD FOR PRODUCING HALOSILANE
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PROBLEM TO BE SOLVED: To provide a method for producing halosilane that can efficiently produce halosilane. SOLUTION: Alkoxy halomethane is used as a halogenating agent and reacted with oxysilane having a structure represented by formula (a), to efficiently produce halosilane having a structure represented by formula (b) (In the formula (b), X is a chlorine atom, a bromine atom, or an iodine atom). SELECTED DRAWING: None COPYRIGHT: (C)2019,JPOandINPIT
- -
-
Paragraph 0028; 0029; 0030; 0031; 0032
(2019/07/31)
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- Nickel-Catalyzed Selective Cross-Coupling of Chlorosilanes with Organoaluminum Reagents
-
Nickel-catalyzed cross-coupling reactions of chlorosilanes with organoaluminum reagents were developed. An electron-rich Ni(0)/PCy3 complex was found to be an effective catalyst for the desired transformation. The reaction of dichlorosilanes 1 proceeded to give the corresponding monosubstituted products 2. Trichlorosilanes 4 underwent selective double substitution to furnish the corresponding monochlorosilanes 2. Overall, the selective synthesis of a series of alkylmonochlorosilanes 2 from di- and trichlorosilanes was achieved using the present catalytic systems.
- Naganawa, Yuki,Guo, Haiqing,Sakamoto, Kei,Nakajima, Yumiko
-
p. 3756 - 3759
(2019/09/12)
-
- Rh(iii)-Catalysed solvent-free hydrodehalogenation of alkyl halides by tertiary silanes
-
Efficient catalytic reduction of CDCl3 and other alkyl halides, including persistent organic pollutants, by different tertiary silanes using the unsaturated silyl-hydrido-Rh(iii) complex {Rh(H)[SiMe2(o-C6H4SMe)](PPh3)2}[BArF4] as a pre-catalyst is accomplished. The reactions are performed in a solvent-free manner. On account of experimental evidence, a simplified catalytic cycle is suggested for the hydrodehalogenation of CDCl3.
- Almenara,Azpeitia,Garralda,Huertos
-
supporting information
p. 16225 - 16231
(2018/11/30)
-
- DMF-activated chlorosilane chemistry: Molybdenum-catalyzed reactions of R3SiH, DMF and R′3SiCl to initially form R′3SiOSiR′3 and R3SiCl
-
The room temperature reactions between R3SiH (R3?=?Et3, PhMe2, Ph2Me) and R′3SiCl (R′3?=?Me3, PhMe2, Ph2Me), with an excess of dimethylformamide (DMF) in the presence of (Me3N)Mo(CO)5 as a catalyst, result in the initial formation of R3SiCl, R′3SiOSiR′3 and Me3N as detected by 29Si, 13C, 1H NMR spectroscopy and GC/MS. As the reaction proceeds, the more so if the reaction temperature is raised, mixed disiloxanes R3SiOSiR′3 and ultimately lesser amounts of R3SiOSiR3 may be detected. A mechanism involving the activation of chlorosilanes by the nucleophilic DMF is proposed to produce transient imminium siloxy ion pairs, [Me2N[dbnd]CHCl]+[R′3SiO]? ? [Me2N[dbnd]CH(OSiR′3)]+Cl? which react with R3SiH to form Me2NCH2OSiR′3 and R3SiCl. A secondary reaction of Me2NCH2OSiR′3 with R′3SiCl produces the symmetrical disiloxane R′3SiOSiR′3 and ClCH2NMe2. The final stage of the reaction is the reduction of ClCH2NMe2 by R3SiH, a reaction which is reported for the first time. The newly created chlorosilane R3SiCl can become involved in the initial DMF activation chemistry thereby forming the other disiloxanes observed as the reaction proceeds.
- Gonzalez, Paulina E.,Sharma, Hemant K.,Pannell, Keith H.
-
supporting information
p. 376 - 381
(2017/06/30)
-
- Method of preparation of phenyl dimethylchlorosilane
-
The invention discloses a method for preparing phenyl dimethylchlorosilane. The method for preparing phenyl dimethylchlorosilane comprises the following steps of: carrying out a Grignard reaction on chlorobenzene and magnesium so as to generate a Grignard reagent, and carrying out condensation reaction on the obtained Grignard reagent and dimethyl dichlorosilane under a novel catalyst so as to generate the phenyl dimethylchlorosilane; and carrying out the Grignard reaction and the condensation reaction respectively in a solvent system formed by methyl tertiary butyl ether and/or 2-methyltetrahydrofuran. Through adopting the solvent formed by methyl tertiary butyl ether and/or 2-methyltetrahydrofuran for reaction, when the Grignard reaction and the condensation reaction are carried out, the side reaction is less, and the reaction is much slow and is easy to control; the productivity of phenyl dimethylchlorosilane is improved; and the waste liquid amount during the production process is reduced.
- -
-
Paragraph 0027-0029
(2017/02/24)
-
- Direct evidence for intermolecular oxidative addition of σ(Si-Si) bonds to gold
-
Oxidative addition plays a major role in transition-metal catalysis, but this elementary step remains very elusive in gold chemistry. It is now revealed that in the presence of GaCl3, phosphine gold chlorides promote the oxidative addition of disilanes at low temperature. The ensuing bis(silyl) gold(III) complexes were characterized by quantitative 31P and 29Si NMR spectroscopy. Their structures (distorted Y shape) and the reaction profile of σ(Si-Si) bond activation were analyzed by DFT calculations. These results provide evidence for the intermolecular oxidative addition of σ(Si-Si) bonds to gold and open promising perspectives for the development of new gold-catalyzed redox transformations. Oxidative addition is the most elusive elementary step in reactions with gold. Now, evidence for the intermolecular oxidative addition of σ(Si-Si) bonds is reported. Phosphine gold chlorides readily reacted with disilanes at low temperature in the presence of GaCl3. The ensuing bis(silyl) gold(III) complexes were characterized by 31P and 29Si NMR spectroscopy, and their structures were analyzed by DFT calculations. Copyright
- Joost, Maximilian,Gualco, Pauline,Coppel, Yannick,Miqueu, Karinne,Kefalidis, Christos E.,Maron, Laurent,Amgoune, Abderrahmane,Bourissou, Didier
-
p. 747 - 751
(2014/01/23)
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- Chemo- and regioselective catalytic reduction of N-heterocycles by silane
-
The ruthenium complex [Cp(iPr3P)Ru(NCCH3) 2]+ (1) catalyzes the regioselective hydrosilylation of pyridines to 1,4-dihydropyridines. Substitution in the 3- and 5-positions is tolerated, whereas pyridines with substituents in the 2-, 4-, and 6-positions are not reduced. Reduction of functionalized pyridines having keto and ester substituents results in a mixture of products. N-Silyl-1,4-dihydropyridine reacts with ketones and aldehydes to give products of N-Si addition across the C=O bond. Hydrosilylation of pyridine in acetone results quantitatively in the addition product PhMe2SiO-CMe2-NC5H 6, which decomposes in hexane to give the parent dihydropyridine HNC5H6. The phenanthroline complex [Cp(phen)Ru(NCCH 3)2]+ (10) catalyzes regioselective 1,4-reduction of phenanthroline by a 3-4-fold excess of silane/water or silane/alcohol mixtures. The Cp* analogue [Cp*(ph n)Ru(NCCH 3)2]+ (9) catalyzes 1,4-regioselective monohydrosilylation of phenanthroline, quinoline, acridine, and 1,3,5-triazine and the 1,2-reduction of isoquinoline. In contrast, 2-substituted phenanthroline, pyrazine, 2-ethylpyridine, 2,6-lutidine, 2,4-lutidine, and pyrimidine are not reduced under these conditions by either of the catalysts studied.
- Lee, Sun-Hwa,Gutsulyak, Dmitry V.,Nikonov, Georgii I.
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p. 4457 - 4464
(2013/09/23)
-
- Synthesis and cytotoxicity studies of silyl-substituted titanocene dichloride derivatives
-
Six new titanocene compounds have been isolated and characterized. These compounds were synthesized from their silyl-substituted fulvene or cyclopentadiene precursors using Super Hydride (LiBEt3H) or n-BuLi, followed by transmetalation with titanium tetrachloride, to yield the corresponding titanocene dichloride derivatives. These complexes are bis-[((phenyl)dimethylsilane)cyclopentadienyl] titanium(IV) dichloride (3a), bis-[((4-methoxyphenyl)dimethylsilane)cyclopentadienyl] titanium(IV) dichloride (3b), bis-[((4-N,N-dimethylmethanamine)dimethylsilane)cyclopentadienyl] titanium(IV) dichloride (3c), bis-[((4-N,N-diethylmethanamine)dimethylsilane) cyclopentadienyl] titanium(IV) dichloride (3d), bis-[((1-methyl-5- trimethylsilyl)indol-3-yl)methylcyclopentadienyl] titanium(IV) dichloride (4e), and bis-[((1-methyl-3-diethylaminomethyl-5-trimethylsilyl)indol-2-yl) methylcyclopentadienyl] titanium(IV) dichloride (4f). The two titanocenes 3a and 3b were crystallized and characterized by X-ray crystallography, while all six titanocenes were tested for their cytotoxicity through MTT-based in vitro tests on CAKI-1 cell lines in order to determine their IC50 values. Titanocenes were found to have IC50 values of 139 (±5), 106 (± 4), 127 (±4), 104 (±9), 90 (±6), and 15 (±2) μM.
- Deally, Anthony,Hackenberg, Frauke,Lally, Grainne,Mueller-Bunz, Helge,Tacke, Matthias
-
p. 5782 - 5790,9
(2020/08/31)
-
- Hexachloroethane: a highly efficient reagent for the synthesis of chlorosilanes from hydrosilanes
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A new and efficient chlorination protocol is presented for the preparation of chlorosilanes from hydrosilanes. A variety of chlorinating agents in combination with palladium(II) chloride as the catalyst are examined. Among them, hexachloroethane is found to be the best choice, furnishing the desired product in good to quantitative yields under mild conditions. Various hydrosilanes are used as starting materials to explore the scope of this reaction.
- Pongkittiphan, Veerachai,Theodorakis, Emmanuel A.,Chavasiri, Warinthorn
-
scheme or table
p. 5080 - 5082
(2009/12/01)
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- Modular approach to silicon-bridged biaryls: Palladium-catalyzed intramolecular coupling of 2-(arylsilyl)aryl triflates
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(Chemical Equation Presented) Bridge of Si: Intramolecular direct arylation of 2-(arylsilyl)aryl triflates is catalyzed smoothly by Pd(OAc) 2/PCy3 in the presence of Et2NH in dimethylacetamide (DMA), giving rise to the corresponding silicon-bridged biaryls in good to excellent yields. The new approach has led to the synthesis of a silicon-bridged 2-phenylindole (see scheme) that exhibits blue photoluminescence in the solid state with extremely high quantum yields.
- Shimizu, Masaki,Mochida, Kenji,Hiyama, Tamejiro
-
supporting information; body text
p. 9760 - 9764
(2009/05/30)
-
- SURFACE MODIFIED ORGANIC·INORGANIC HYBRID GLASS, PROTECTING GROUP INDUCED ALCOHOL OR ITS DERIVATIVE AND PRODUCING METHOD THEREOF
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Disclosed are a protected alcohol or derivative thereof, a surface- modified organic-inorganic hybrid glass, and preparation methods thereof. More specifically, disclosed are a protected alcohol or derivative thereof and a surface-modified organic-inorganic hybrid glass, which are prepared by allowing a silane compound, having vinyl or a vinyl derivative, to react with an alcohol or derivative thereof or with an organic-inorganic hybrid glass, in the presence of an acid catalyst, a transition metal catalyst and an organic solvent, so as to introduce an organic group thereto even at room temperature, as well as preparation methods thereof. The disclosed invention allows a functional group to be effectively introduced into alcohol or a derivative thereof or into an organic-inorganic hybrid glass, not only high temperatures but also room temperature, and thus is highly effective in introducing compounds having a thermally sensitive functional group, for example, natural compounds or proteins. Also, the invention makes it possible to introduce various organic groups and to separate and purify organic macromolecule-bonded organosilane compounds using a silica gel column so as to effectively introduce large organic functional groups to inorganic materials. Accordingly, the invention is highly useful in the chemical industry.
- -
-
Page/Page column 13-14; 42-43; 1;3
(2010/11/28)
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- Highly efficient O-silylation of alcohol with vinylsilane using a Rh(l)/HCl catalyst at room temperature
-
Highly efficient O-silylation of alcohol with vinylsilane was developed using a catalyst system consisting of [(COE)2RhCl]2 and HCl. In this reaction, a key intermediate is chlorosilane, generated from vinylsilane and HCl, which can be regenerated in the catalytic cycle. Various alcohols and vinylsilanes were applied to the preparation of silyl ether compounds with this catalyst system.
- Park, Jung-Woo,Jun, Chul-Ho
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p. 4073 - 4076
(2008/02/11)
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- Palladium-catalyzed silylation of alcohols with hexamethyldisilane
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The combination of hexamethyldisilane and a catalytic amount of [PdCl(η3-C3H5)]2-PPh 3 was found to be effective for the trimethylsilylation of alcohols, where both of the two trimethylsilyl groups of hexamethyldisilane were transferred to alcohols without coproduction of any stoichiometric amount of byproduct but H2. The Royal Society of Chemistry 2006.
- Shirakawa, Eiji,Hironaka, Koji,Otsuka, Hidehito,Hayashi, Tamio
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p. 3927 - 3929
(2007/10/03)
-
- Reactions of organochlorosilanes with chloro-and organogermanes in the presence of aluminum chloride
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The effect of substituents at the silicon and germanium atoms in reactions of organochlorosilanes with chloro-and organogermanes in the presence of aluminum chloride was studied. The only occurring process is the exchange of the chlorine atoms at Ge for the phenyl groups from Si; an increase in the number of methyl groups or chlorine atoms at Si promotes formation of phenyltrichlorogermane, and an increase in the number of phenyl groups or replacement of the chlorine atom at the Si atom by hydrogen leads to the formation of di-and triphenylchlorogermanes. Neither phenyl nor other radicals are transferred back from Ge to Si in the course of reactions of phenylgermanes with methylchlorosilanes in the presence of aluminum chloride; the only occurring processes are the exchange of the phenyl or methyl radicals bonded to Ge for the Cl atom bonded to Al and the disproportionation of phenylchlorogermanes. Nauka/Interperiodica 2006.
- Zhun,Sbitneva,Polivanov,Chernyshev
-
p. 1564 - 1570
(2008/02/09)
-
- Preparation of fluorohalomethylmagnesium halides using highly active magnesium metal and their reactions
-
Highly active magnesium (Rieke magnesium) reacts with fluorohalomethanes at -100°C forming the corresponding fluorohalomethylmagnesium halides, which undergo nucleophilic substitution with silyl halides or nucleophilic addition with aldehydes or ketones. Whereas the stability of dibromofluoromethylmagnesium bromide (2a) was sufficient to provide acceptable product yields with dimethylphenylsilyl chloride, benzaldehyde, butyraldehyde or acetophenone as electrophiles, other fluoroorganomagnesium halides, bromodifluoromethylmagnesium bromide (2b), bromochlorofluoromethylmagnesium bromide (2c) and trifluoromethylmagnesium iodide (2d) displayed only very limited stability and thus the corresponding yields of reactions with electrophiles were low.
- Kví?ala, Jaroslav,?tambasky, Jan,Skalicky, Martin,Paleta, Old?ich
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p. 1390 - 1395
(2007/10/03)
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- Rhodium-catalyzed acylation of vinylsilanes with acid anhydrides
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A catalytic acylation of vinylsilane with acid anhydride is accomplished by the use of [RhCl(CO)2]2, in which the transmetalation between vinylsilane and rhodium(I) carbonyl complex plays a key role. The application of this acylation reaction to (1-acyloxyvinyl)silanes provides synthetic methods for α-acyloxy enones, α-diketones, and their derivatives.
- Yamane, Motoki,Uera, Kazuyoshi,Narasaka, Koichi
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p. 477 - 486
(2007/10/03)
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- Selective synthesis of halosilanes from hydrosilanes and utilization for organic synthesis
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Selective synthesis of halosilanes has been examined. Various types of halosilanes and halohydrosilanes, such as R3SiX, R2SiHX, R2SiX2, RSiH2X, RSiHX2 (X=Cl, Br, F), were obtained by the reactions of the corresponding hydrosilanes with Cu(II)-based reagents selectively in high yields. This method could be also applied to the synthesis of chlorofluorosilanes and chlorohydrogermanes. On the other hand, iodo- and bromosilanes and germanes were obtained by Pd- or Ni-catalyzed hydride-halogen exchange reactions of hydrosilanes with alkyl or allyl halides. Their synthetic applications have been demonstrated by using iodo- and bromosilanes and chlorofluorosilanes.
- Kunai, Atsutaka,Ohshita, Joji
-
-
- C-Cl/Si-H Exchange catalysed by P,N-chelated Pt(II) complexes
-
Alkyl chlorides R-Cl are dehalogenated by HSiMe2Ph in the presence of catalytic amounts of the complex [(κ2-P,N)Ph2PCH2CH2NMe2]PtMeCl to give R-H and ClSiMe2Ph.
- Stoehr, Frank,Sturmayr, Dietmar,Schubert, Ulrich
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p. 2222 - 2223
(2007/10/03)
-
- The preparation of polymer beads by photocationic suspension co-polymerisation of 2-(arylsilyl)ethyl vinyl ethers
-
Polymer beads have been prepared by photocationic suspension polymerisation of 2-(aryldimethyl)silyl ethers in perfluorooctane in the course of our studies on polymer-supported desymmetrisation of 1-silacyclohexa-2,5-dienes. Good yields of 100-200 μm beads of satisfactory shape have been obtained using a perfluorinated co-polymer as stabilising agent. These beads have no permanent porosity although they have a high nominal cross-linking level. Their swelling in common organic solvents is comparable with those of Merrifield or TentaGel gel-type resins.
- Porres, Laurent,Deleuze, Herve,Landais, Yannick
-
p. 2198 - 2203
(2007/10/03)
-
- Tetrabutylammonium butyldifluorodimethylsilicate and difluorodimethylphenylsilicate, new nucleophilic fluorinating reagents
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Tetrabutylammonium butyldifluorodimethylsilicate (TAMBS, 1a) and tetrabutylammonium difluorodimethylphenylsilicate (TAMPS, 1b) were conveniently prepared from the corresponding substituted fluorodimethylsilanes and tetrabutylammonium fluoride. Both fluorosilicates 1a, 1b are powerful nucleophilic fluorinating reagents which transform primary or secondary halides, tosylates, or mesylates to the corresponding fluorides in moderate to good yields.
- Kví?ala,Mysík,Paleta
-
p. 547 - 549
(2007/10/03)
-
- Preparation of 14C-labelled dimethylsilane-1,1-diol
-
The preparation of 14C-labelled dimethylsilane-1,1-diol in two steps from 14C-labelled diphenyldimethylsilane is described. Aluminum chloride catalyzed protodesilylation of diphenyldimethyisilane with HCl in dichloromethane or dimethyldichlorosilane at 0-5°C affords labelled dimethyldichlorosilane which is hydrolyzed in the presence of triethylamine to afford the title compound in 45-60% yield.
- Cella,Carpenter
-
p. 427 - 430
(2007/10/02)
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- REACTION OF ALLYL HALIDES WITH DIMETHYLPHENYLSILANE AND HEXAMETHYLTRISILOXANE IN THE PRESENCE OF HEXACHLOROPLATINIC ACID
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The reaction of dimethylphenylsilane with allyl chloride yields γ-chloropropyldimethylphenylsilane and dimethylphenylchlorosilane, whereas that with allyl bromide results in dimethylphenylbromosilane only.Hydrosilylation of allyl halides with 1,1,3,3,5,5-hexamethyltrisiloxane yields a mixture of various symmetric and asymmetric adducts at both Si-H bonds of the trisiloxane.
- Zavin, B. G.,Pryakhina, T. A.,Strelkova, T. V.,Kireev, V. V.,Astrina, V. I.,Pilipkova, A. Yu.
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p. 568 - 569
(2007/10/02)
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- Triorganomonohalogenosilane
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A triorganomonohalogenosilane is prepared by reacting a triorganomonohydrosilane represented by the following general formula (I): with a halogenated allyl compound represented by the following general formula (II): STR1 in the presence of metal palladium, or a salt or complex of palladium to replace the hydrogen atom directly bonded to the silicon atom of the triorganomonohydrosilane with a halogen atom. In Formula ( I ), the substituents R1 's directly bonded to the silicon atom may be identical to or different from one another and each represents a monovalent organic group. In Formula (II), the substituents R2 's may likewise be identical to or different from one another and each represents a hydrogen atom or a monovalent alkyl group and X represents a chlorine atom, a bromine atom or an iodine atom.
- -
-
-
- Preparation of the iodides (Me3Si)2C(SiMe2C6H4Y)(SiMe2I) and some related compounds
-
The preparations of: (a) the iodides (Me3Si)2C(SiMe2C6H4Y)(SiMe2I) (Y=H, p-OMe, p-Me, p-Cl, m-CF3), via the corresponding hydrides; (b) the compounds (Me3Si)2C(SiMe2Ph)(SiMe2X) with X=F, O2CCF3, OMe, N3, NCS and Cl: and (c) the iodide (p-MeC6H4)3CSiMe2I are described. Key words: Silicon; Iodide; Fluoride; Hydride; Trimethylsilyl
- Eaborn, Colin,Jones, Karen L.,Lickiss, Paul D.
-
-
- Electrochemical Oxidation of Hydrosilanes. A Synthetic Approach to Halosilanes and Disilanes
-
Electrolytic oxidation of dimethylphenylsilane (1) in the presence of CuCl2 or CuCl afforded chlorodimethylphenylsilane in high yields (>90percent), while similar electrolysis of 1 in the presence of BF4- ions afforded fluorodimethylphenylsilane in 90percent yield. 1,2-Diphenyltetramethyldisilane was obtained from 1 in 48percent yield by the electrolysis with a Pt-Cu electrode system.A "paired" electrolysis of methyldiphenylsilane on the anode and chloromethyldiphenylsilane on the cathode afforded 1,2-dimethyltetraphenyldisilane in 64percent yield.
- Kunai, Atsutaka,Kawakami, Toshihiro,Toyoda, Eiji,Sakurai, Tomohiro,Ishikawa, Mitsuo
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p. 1945 - 1948
(2007/10/02)
-
- Photochemical reactions of aryl-substituted catenates of group 4B elements, PhMe2E-E'Me3 (E, E' = Si and Ge). Formation of a radical pair
-
Photochemical reactions of phenyl substituted catenates of group 4B elements, PhMe2E-E'Me3 (E, E' = Si and Ge) have been investigated by chemical trapping experiments and laser flash-photolysis.On irradiation, the phenylated group 4B catenate undergoes E-E' bond homolysis to give a pair of radicals (PhMe2E. and Me3E'.).In CCl4, these radicals are converted to the corresponding chlorides by abstraction of a chlorine atom.In a nonhalogenated solvent, the radical pair couples at the ipso-position of the phenyl group of the pairing radical (PhMe2E.) to yield the cor responding diradical.This undergoes either elimination of a divalent species (Me2E:) with concomitant formation of trimethylphenyl group 4B element PhMe3E') or intramolecular 1,2-group 4B element migration to yield group 4B metal-carbon double bonded species.The radical escapes from the solvent cage coupled to the metal atom of the radical to yield the dimetallic product.The reaction path observed is highly dependent on the nature of the group 4B element comprising the phenyl substituted catenate.
- Mochida, Kunio,Kikkawa, Haruhiko,Nakadaira, Yasuhiro
-
-
- Palladium-Catalyzed Reductive Coupling of Aromatic Acid Dichlorides with Disilanes
-
Electron-deficient aromatic acid-chlorides are converted to biphenyl compounds by palladium-catalyzed reaction with disilanes.
- Krafft, Terry E.,Rich, Jonathan D.,McDermott, Philip J.
-
p. 5430 - 5432
(2007/10/02)
-
- Silylative Decarbonylation: A New Route to Arylsilanes
-
A new synthetic procedure for the preparation of aromatic chlorosilanes via the palladium-catalyzed reaction of methylchlorodisilanes and aromatic acid chloride is described.The silylative decarbonylation process is solventless, can utilize low metal catalyst loadings (500-1000 ppm Pd), is carried out under moderate conditions (145 deg C), and selectively gives aromatic chlorosilanes in good yield, generally 60-85percent.The procedure is tolerant of a variety of aromatic substituents, for example, alkyl, halo, nitro, cyano, imide, acid anhydride, etc., and the synthesis ofseveral new substituted aromatic chlorosilanes containing benzoyl chloride and phthalic anhydride moieties is described.Chloromethyldisilane starting reagents are available from the direct reaction of methyl chloride and silicon, making this methodology an attractive synthetic route to functionalized aromatic chlorosilanes.
- Rich, Jonathan D.
-
p. 5886 - 5893
(2007/10/02)
-
- Zur Synthese von Siloxanen XIV. Die Umsetzung von Chlorsilanen mit Silanolen im sauren Medium
-
The reactions of aryldimethylchlorosilanes with benzyldimethylsilanol in C6D6/dioxane (2.8/1) have been investigated by 1H NMR spectroscopy.Fast substituent exchange reactions were observed in the presence of H2O or HCl.In this process both substances establish chlorosilane/silanol equilibria which are related to the concetration of H2O and HCl formed.A ρ-value of 1.3 was found for the reaction of substituted aryldimethylchlorosilanes with benzyldimethylsilanol in the presence of H2O.In time the equilibria are disturbed by condensation processes.
- Ruehlmann, K.,Grosse-Ruyken, H.,Scheller, D.,Scheim, U.
-
-
- Synthesis of siloxanes. XII. Cleavage of siloxanes by hydrogen chloride
-
1H NMR spectroscopy has been used in a kinetic study of the cleavage of siloxane bonds by hydrogen chloride in dioxane.The cleavages show an induction period which is associated with the autocatalytic effect of the water formed during the reaction.The kinetic behavior can be expressed in terms of a rate law that includes rate constants for cleavage by both dioxane*HCl (k1) and H2O*HCl (k2).The k'1 (k'1 = k1*-4) and k'2 (k'2 = k2*-3) values correlate with ?* values; thus ρ* values of -1.4 and -0.7 were obtained for k'1 and k'2, respectively.The ?* value of 0.35 that we previously derived for the Me3SiO group applies in this reaction.The reaction of 1,3-bis(p-methoxyphenyl)tetramethyldisiloxane with hydrogen chloride involves cleavage of silicon-aryl rather than Si-O bonds.
- Scheim, U.,Lehnert, R.,Porzel, A.,Ruehlmann, K.
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p. 141 - 150
(2007/10/02)
-
- REACTIONS IN THE CHLOROSILANE-SILANOL-SILOXANE SYSTEM
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We obtained the first ?*-values and ES-values for siloxy groups by spectroscopic and kinetic methods.Detailed mechanistic investigations are performed on the hydrolysis of chlorosilanes, the cleavage of Si-O-Si bonds by HCl, and the substituent exchange reaction between silanols and chlorosilanes.
- Ruehlmann, K.
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p. 139 - 152
(2007/10/02)
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- NOUVELLES UTILISATIONS DU TETRAMETHYLSILANE COMME AGENT DE METHYLATION DES CHLOROSILANES; VALORISATION DU METHYLTRICHLOROSILANE
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In the presence of catalytic amounts of AlCl3, the chlorosilanes MeSiCl3, ClMe2SiCH2Cl and PhSiCl3 convert Me4Si into Me3SiCl.In the first case, at 130 deg C, two by-products from the industrial synthesis of Me2SiCl2 provide the useful Me3SiCl as the unique product with a 44percent conversion ratio from Me4Si.From ClMe2SiCH2CL, the only products formed are Me3SiCl and Me3SiCH2Cl, which is a useful reagent for organic syntheses (formation ratio: 32percent), if the reaction is performed under atmospheric pressure, but if an autoclave is used EtMe2SiCl (88percent maximal yield) is obtained.
- Bordeau, M.,Djamei, S. M.,Calas, R.,Dunogues, J.
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p. 131 - 138
(2007/10/02)
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- On the Thermal Behaviour of Some (Methylphenylsilyl)methyl Carbonate Derivatives
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The synthesis and the thermal behaviour of the (methylphenylsilyl)methyl carbonates CH3(C6H5)Si(H)CH2OC(O)X (6: X = OCH3; 7: X = Cl; 8: X = N(CH3)2) is described. 8 rearranges in toluene solution at 100 deg C quantitatively to give the carbamoyloxysilane C6H5(CH3)2SiOC(O)N(CH3)2 (11), whereas neat 6 and 7 at 135 deg C undergo quantitative formation of C6H5(CH3)2SiOCH3 (12) and C6H5(CH3)2SiCl (13), respectively.The formation of 12 and 13 is explained by a rearrangement reaction (by analogy to the rearrangement of 8), followed by a decarboxylation.The thermally induced transformations 6-->12, 7-->13, and 8-->11 were found to be first-order reactions with half-lifes of ca. 2.6 h (135 deg C, neat), ca. 4.5 h (135 deg C, neat), and ca. 3.7 h (100 deg C, in toluene), respectively. - Keywords: (Methylphenylsilyl)methyl Carbonates, Rearrangement, Dimethylphenylsilyl Carbonates, Decarboxylation
- Tacke, Reinhold,Link, Matthias,Bentlage-Felten, Anke,Zilch, Harald
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p. 942 - 947
(2007/10/02)
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- REACTIONS OF TELLURIUM(IV) CHLORIDES WITH SOME ORGANOSILICON HYDRIDES
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The reactions of several organosilicon hydrides PhnSiH(4-n), n = 1, 2; R3SiH, R3 = Ph3, Ph2Me, PhMe2, (n-C6H13)3; (p-Me2HSi)2C6H4, with TeCl4 in benzene resulted in the formation of tellurium metal and chlorosilanes in 75-90percent yields.Similar reactions with aryltellurium trichlorides (RTeCl3, R = Ph, p-MeOC6H4, p-EtOC6H4) proceeded in two different ways.On stirring at room temperature for 6-8 h, diaryl ditellurides and chlorosilanes were obtained in 70-95percent yields whereas on refluxing for 6-10 h, tellurium powder and diaryltellurium dichlorides were obtained along withthe chlorosilanes in 80-95percent yields.Diaryltellurium dichlorides (R2TeCl2, R = Ph, p-MeOC6H4) did not react readily with PhSiH3 nor with Ph3SiH.
- Chadha, Raj K.,Drake, John E.,Neo, Mary K. H.
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- INSERTION REACTIONS OF CALCIUM ATOM INTO Si-Cl AND Ge-Cl BONDS
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Calcium atom is inserted into Si-Cl and Ge-Cl bonds of organosilylchlorides and organogermylchlorides to give the corresponding organosilylcalcium chlorides and organogermylcalcium chlorides, respectively.
- Mochida, Kunio,Manishi, Masaharu
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p. 1077 - 1080
(2007/10/02)
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- Thermally Induced Rearrangement of (Acyloxymethyl)diorganylsilanes
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The (acyloxymethyl)diorganylsilanes R1R2Si(H)CH2OC(O)R3 (2a-d) rearrange to the corresponding acyloxy(methyl)diorganylsilanes R1R2Si(CH3)OC(O)R3 (3a-d).This reaction is formally equivalent to an exchange of the hydrogen bound to silicon and acyloxy group bound to carbon.The 1,2-hydrogen shift could be shown experimentally to be an intramolecular process.
- Tacke, Reinhold,Lange, Hartwig
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p. 3685 - 3691
(2007/10/02)
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