- Hydrogenation of chlorosilanes by NaBH4
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Hydrogenation of chlorosilane was achieved in acetonitrile using NaBH4, a safe and easy-to-handle reagent. This reaction converted Si-Cl portion(s) in organosilanes into Si-H portion(s) without hydrogenation of cyano, chloro, and aldehyde groups on an alkyl substituent of the Si reagents. In addition, the Si-Cl/Si-H exchange reaction was applicable to dichlorodisilane without Si-Si bond cleavage.
- Ito, Masaki,Itazaki, Masumi,Abe, Takashi,Nakazawa, Hiroshi
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Read Online
- PROCESS FOR THE STEPWISE SYNTHESIS OF SILAHYDROCARBONS
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The invention relates to a process for the stepwise synthesis of silahydrocarbons bearing up to four different organyl substituents at the silicon atom, wherein the process includes at least one step a) of producing a bifunctional hydridochlorosilane by a redistribution reaction, selective chlorination of hydridosilanes with an ether/HCI reagent, or by selective chlorination of hydridosilanes with SiCI4, at least one step b) of submitting a bifunctional hydridochloromonosilane to a hydrosilylation reaction, at least one step c) of hydrogenation of a chloromonosilane, and a step d) in which a silahydrocarbon compound is obtained in a hydrosilylation reaction.
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Page/Page column 54; 57
(2021/12/08)
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- CATALYTIC REDUCTION OF HALOGENATED CARBOSILANES AND HALOGENATED CARBODISILANES
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Selective reduction methods for halogenated carbosilanes and carbodisilanes are disclosed. More particularly, high yields of the desired carbosilanes and carbodisilanes are obtained by reduction of their halogenated counterparts using a reducing agent and tetrabutylphosphonium chloride (TBPC) as a catalyst.
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Paragraph 0070; 0071
(2021/04/02)
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- Borohydride catalyzed redistribution reaction of hydrosilane and chlorosilane: A potential system for facile preparation of hydrochlorosilanes
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Various borohydrides were found to catalyze the redistribution reaction of hydrosilane and chlorosilane in different solvents to produce hydrochlorosilanes efficiently and facilely. The redistribution reaction was affected by solvent and catalyst. The substrate scope was investigated in HMPA with LiBH4 as catalyst. A possible mechanism was proposed to explain the redistribution process.
- Ai, Liqing,Chen, Yi,Li, Yongming,Xu, Caihong
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p. 17404 - 17407
(2020/06/19)
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- Facile preparation of hydrochlorosilane by alkali metal halide catalyzed Si-H/Si-Cl redistribution reaction
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Various alkali metal halides were found to catalyze the Si-H/Si-Cl redistribution reaction in different polar solvents efficiently. The scope of silane substrate was studied using KF as catalyst and 18-crown-6 as cocatalyst in DMI. The alkali metal halides catalyzed redistribution system provides a useful method to prepare hydrochlorosilanes more facilely. A possible mechanism was proposed to explain the process.
- Chen, Yi,Li, Yongming,Xu, Caihong
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supporting information
(2020/09/21)
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- SYNTHESIS OF ORGANO CHLOROSILANES FROM ORGANOSILANES
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The invention relates to a process for the production of chlorosilanes by subjecting one or more hydndosilanes to the reaction with hydrogen chloride in the presence of at least one ether compound, and a process for the production of such hydndosilanes serving as starting materials.
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Page/Page column 36; 37; 38; 39; 40; 47
(2019/04/16)
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- Neutral-Eosin-Y-Photocatalyzed Silane Chlorination Using Dichloromethane
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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
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supporting information
p. 12580 - 12584
(2019/08/16)
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- Lewis Base Catalyzed Selective Chlorination of Monosilanes
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A preparatively facile, highly selective synthesis of bifunctional monosilanes R2SiHCl, RSiHCl2 and RSiH2Cl is reported. By chlorination of R2SiH2 and RSiH3 with concentrated HCl/ether solutions, the stepwise introduction of Si?Cl bonds is readily controlled by temperature and reaction time for a broad range of substrates. In a combined experimental and computational study, we establish a new mode of Si?H bond activation assisted by Lewis bases such as ethers, amines, phosphines, and chloride ions. Elucidation of the underlying reaction mechanisms shows that alcohol assistance through hydrogen-bond networks is equally efficient and selective. Remarkably, formation of alkoxysilanes or siloxanes is not observed under moderate reaction conditions.
- Sturm, Alexander G.,Schweizer, Julia I.,Meyer, Lioba,Santowski, Tobias,Auner, Norbert,Holthausen, Max C.
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supporting information
p. 17796 - 17801
(2018/11/23)
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- Hydrosilane synthesis via catalytic hydrogenolysis of halosilanes using a metal-ligand bifunctional iridium catalyst
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Hydrogenolysis of various halosilanes was catalysed by iridium amido complexes to produce hydrosilanes. Selective monohydrogenolysis of di- and trichlorosilanes similarly proceeded, resulting in the formation of chlorohydrosilanes (R2SiHCl or RSiHCl2) as synthetically important building blocks for various organosilicon compounds. A mechanistic study supported the in-situ formation of an iridium hydride species as a key intermediate, which could transfer the hydride to the silicon atom through a metal–ligand bifunctional mechanism. One-pot hydrotrimethylsilylation of olefins was achieved via successive hydrogenolysis and hydrosilylation reactions starting from Me3SiCl.
- Beppu, Teruo,Sakamoto, Kei,Nakajima, Yumiko,Matsumoto, Kazuhiro,Sato, Kazuhiko,Shimada, Shigeru
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- By the hydrogen-containing silane-efficient and controllable synthetic chlorosilane method (by machine translation)
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The invention relates to a method of synthesizing chlorosilane from hydrogen-containing silane. The method comprises the step of enabling the hydrogen-containing silane to react with copper chloride in the presence of inert material particles. Dosage of a solvent is greatly lowered (only 0-150 ml of solvent is needed for synthesizing every 0.1 mol of chlorosilane), and even the solvent can be not used, and the reaction can be carried out as long as liquid silane can completely soak solid materials. Reaction time is greatly shortened and side reactions are less. Meanwhile, conversation rate of the reaction is greatly improved, and yield of a purified product is higher.
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Paragraph 0043; 0044
(2017/12/02)
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- B(C6F5)3-Catalyzed Selective Chlorination of Hydrosilanes
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The chlorination of Si?H bonds often requires stoichiometric amounts of metal salts in conjunction with hazardous reagents, such as tin chlorides, Cl2, and CCl4. The catalytic chlorination of silanes often involves the use of expensive transition-metal catalysts. By a new simple, selective, and highly efficient catalytic metal-free method for the chlorination of Si?H bonds, mono-, di-, and trihydrosilanes were selectively chlorinated in the presence of a catalytic amount of B(C6F5)3 or Et2O?B(C6F5)3 and HCl with the release of H2 as a by-product. The hydrides in di- and trihydrosilanes could be selectively chlorinated by HCl in a stepwise manner when Et2O?B(C6F5)3 was used as the catalyst. A mechanism is proposed for these catalytic chlorination reactions on the basis of competition experiments and density functional theory (DFT) calculations.
- Chulsky, Karina,Dobrovetsky, Roman
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supporting information
p. 4744 - 4748
(2017/04/11)
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- An efficient method to synthesize chlorosilanes from hydrosilanes
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An efficient, highly selective and productive synthesis of chlorosilanes from hydrosilanes is reported. Ceramic spheres were added to chlorination reaction systems and found to greatly increase the efficiency and yields of the reactions. PhSiH2Cl, PhSiHCl2, PhSiCl3, Ph 2SiHCl, Ph2SiCl2, PhMeSiHCl and PhMeSiCl 2 were synthesized from the corresponding hydrosilanes in only a few hours with yields that typically exceeded 90%. This is the first time PhSiCl3, Ph2SiHCl, Ph2SiCl2 and PhMeSiCl2 have been synthesized by this method. The factors that affect the rate of the chlorination reaction were studied. In addition the rate constant, reaction order and apparent activation energy of the chlorination reaction were also determined by kinetics study. The reaction was found to have an induction period.
- Wang, Wenchao,Tan, Yongxia,Xie, Zemin,Zhang, Zhijie
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- Preparation and reactivity of an O,O-chelating silsesquioxane-palladium complex
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An incompletely condensed silsesquioxane containing trisilanol (c-C 5H9)7Si7O9(OH) 3 reacts with [PdI2(bpy)] (bpy = 2,2′-bipyridine) in the presence of Ag2O to produce a palladium complex with an O,O-chelating silsesquioxanate ligand, [Pd{O11Si7(c-C 5H9)7(OH)}(bpy)] (1). The reaction of Ph 2SiClH with 1 in 2:1 ratio causes disilylations of the silsesquioxanate ligand, forming [PdCl2(bpy)]. Addition of p-cresol to a solution of 1 yields the trisilanol and [Pd(OC6H 4CH3-p)2(bpy)].
- Tanabe, Makoto,Mutou, Kohji,Mintcheva, Neli,Osakada, Kohtaro
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p. 1211 - 1215
(2011/04/22)
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- Hydrogen-bonding 3D networks by polyhedral organosilanols: Selective inclusion of hydrocarbons in open frameworks
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Tetrahedral organosilanols E[C6H4Si(i-Pr) 2OH]4 (E = C, 2a; E = Si, 2b) as well as octahedral organosilanols Si8O12(CH=CHC6H 4SiR2OH)8 (R = i-Pr, 5a; R = Ph, 5b) have been derived from tetraphenylmethane and -silane (1a,b) and octavinyloctasilsesquioxane (3) designed for self-assembly of 3D hydrogen-bonding networks possessing large porosity. X-ray analyses following crystallization of 2a,b from THF/benzene and either hexane or heptane revealed adamantane-type networks with hydrogen bonds between the silanols of four separate molecules and selective inclusion of hexane or heptane, respectively. Upon changing the mixed solvent to THF/benzene/cyclohexane, X-ray analysis of 2a showed an inclusion compound of composition 2a·1.5benzene. TOPOS analyses of 2a·1.5benzene demonstrated a non-adamantane-type framework with sra network topology. Crystallization of 5a,b from acetone/benzene followed by X-ray analyses confirmed the production of the inclusion compounds 5a·18benzene and 5b·23benzene. The open frameworks of 5a·18benzene and 5b·23benzene are constructed with zeolitic or fluorite cages, and ast or flu network topology results, based on the TOPOS program. The packing of benzene molecules in 5a·18benzene and 5b·23benzene was found to be similar to that of crystals of pure benzene in edge-to-face arrangements. Thus, hydrogen-bonding networks of polyhedral organosilanols have shown selective inclusion of hydrocarbons into large cavities with adjustable porosity and without interpenetration of one network into another.
- Kawakami, Yoshiteru,Sakuma, Yoshinobu,Wakuda, Takashi,Nakai, Tatsuya,Shirasaka, Masayoshi,Kabe, Yoshio
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experimental part
p. 3281 - 3288
(2010/09/06)
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- GRIGNARD PROCESSES WITH IMPROVED YIELDS OF DIPHENYLCHLOROSILANES AS PRODUCTS
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A Grignard process for preparing phenyl-containing chlorosilane products, in particular diphenylchlorosilanes, is carried out in three embodiments. In the first embodiment, the reactants of the Grignard process are a phenyl Grignard reagent, an ether solvent, a trichlorosilane, and an aromatic hydrocarbon coupling solvent. In the second embodiment, the reactants of the Grignard process are a phenyl Grignard reagent, an ether solvent, a phenylchlorosilane, and an aromatic hydrocarbon coupling solvent. In the third embodiment, the reactants of the Grignard process are a phenyl Grignard reagent, an ether solvent, a trichlorosilane, a phenylchlorosilane, and an aromatic hydrocarbon coupling solvent. In each embodiment, the reactants are present in a particular mole ratio.
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Page/Page column 9
(2008/06/13)
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- Intramolecular radical-chain hydrosilylation catalysed by thiols: Cyclisation of alkenyloxysilanes
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Alkenyloxy(diphenyl)silanes that contain a terminal double bond undergo radical-chain cyclisation at 60-65°C, in the presence of di-tert-butyl hyponitrite as initiator and a thiol as a catalyst. The thiol acts as a polarity-reversal catalyst and promotes the overall abstraction of hydrogen from the Si-H group in the alkenyloxysilane by the cyclic carbon-centred radical, formed by intramolecular addition of the corresponding silyl radical to the C=CH2 group. Allyloxysilanes give five-membered-ring products via 5-endo-trig cyclisation of the intermediate allyloxysilyl radical. Homoallyloxysilanes give mixtures of five- and six-membered heterocycles, but the intermediate silyl radicals undergo predominantly 6-endo cyclisation, in contrast to the corresponding carbon-centred radicals which cyclise preferentially in the 5-exo mode. An analogous pentenyloxysilane gives only the seven-membered-ring product via a 7-endo radical cyclisation. Steric effects play an important part in influencing the final-product stereochemistry when this is determined in the hydrogen-atom transfer reaction between the cyclic adduct radical and the thiol catalyst. Complementary EPR spectroscopic studies of the short-lived intermediate cyclic adduct radicals have been carried out in the absence of thiol and the structures and conformations of these species have been determined. It is emphasised that, for thiol catalysis of the overall cyclisation of alkenyloxysilanes to be successful, it is necessary for the addition of the chain-carrying thiyl radical to the C=CH2 group to be reversible under the reaction conditions.
- Cai, Yudong,Roberts, Brian P.
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p. 467 - 475
(2007/10/03)
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- Stereocontrol in organic synthesis using silicon-containing compounds. A formal synthesis of prostaglandins controlling the stereochemistry at C-15 using a silyl-to-hydroxy conversion following a stereochemically convergent synthesis of an allylsilane
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Hydrosilylation of isoprene with chloro(diphenyl)silane gave (Z)-chloro(2-methylbut-2-enyl)-diphenylsilane 7. The cuprate reagent derived from this chloride underwent conjugate addition to methyl cinnamate 11, 1,2-silylcupration with hex-1-yne 16 and allene 18, and allylic displacement reactions with 1-vinylcyclohexyl acetate 20 and (Z)-1-cyclopentyloct-2-en-1-yl acetate 22. The silyl group in each of the products was converted into a hydroxy, with the removal of the 2-methylbut-2-enyl group taking place under much milder acidic conditions than those needed to remove the phenyl group from the dimethyl(phenyl)silyl group, and making this group suitable for the conversion of an allylsilane into an allyl alcohol. A stereospecifically anti conjugate displacement of the allylic benzoate group in (Z)-(1S,5R,6R,7R,1′S)-7-benzoyloxy-6-(1′-benzoyloxyoct-2′- enyl)-2-oxabicyclo[3.3.0]octan-3-one 52, and a stereospecifically syn conjugate displacement of the carbamate group in (Z)-(1S,5R,6R,7R,1′R)-7-benzoyloxy-6-(1′-N-phenylcarbamoyloxyoct- 2′-enyl)-2-oxabicyclo[3.3.0]octan-3-one 51, gave stereo-convergently the same allylsilane (1′ E,2″Z)-(1S,5S,6R,7R,3′S)-7-benzoyloxy-6-[3′-(2″- methylbut-2″-enyl)-diphenylsilyloct-1′-enyl]-2-oxabicyclo[3.3.0] octan-3-one 53. Silyl-to-hydroxy conversion gave the allyl alcohol (E)-(1S,5S,6R,7R,3′S)-7-benzoyloxy-6-(3′-hydroxyoct-1′-enyl)- 2-oxabicyclo[3.3.0]octan-3-one 54, having the relative and absolute stereochemistry at C-15 of the prostaglandins.
- Fleming, Ian,Winter, Stephen B. D.
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p. 2687 - 2700
(2007/10/03)
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- Process for preparing cyclopentadienyl group-containing silicon compound or cyclopentadienyl group-containing germanium compound
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Disclosed is a process for preparing a cyclopentadienyl group-containing silicon compound or a cyclopentadienyl group-containing germanium compound, comprising reacting (i) a lithium, sodium or potassium salt of a cyclopentadiene derivative with (ii) a silicon halide compound or a germanium halide compound in the presence of a cyanide or a thiocyanate. The cyanide or the thiocyanate is preferably a copper salt. According to the process of the invention, a cyclopentadienyl group-containing silicon compound or a cyclopentadienyl group-containing germanium compound, which is very useful for the preparation of a metallocene complex catalyst component, can be prepared in a high yield for a short period of time.
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- Generation and Detection of the Silaethene Ph2Si=C(SiMe3)2
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Bromotrisilylmethanes (Me3Si)2(Ph2XSi)CBr (4-13; Table 1) are formed by the reaction of (Me3Si)2(Ph2HSi)CM (M = Li, Na) with bromine or with bromine/chlorine (X = H, Cl, Br) and also by treating (Me3Si)2(Ph2BrSi)CBr with KHF2 (X = F), H2O or MeOH (X = OH, OMe), MeLi (X = Me), BuLi/Br2 (X = Bu), PhLi/Br2 or PhLi/PhOLi/Br2 (X = Ph, OPh).PhLi, BuLi, and tBu3SiNa convert the bromotrisilylmethanes by Br/M exchange into compounds (Me3Si)2(Ph2XSi)CM, which may be protolyzed, alkylated, and brominated .For X = halogen the equilibrium (Me3Si)2(Ph2XSi)CM Ph2Si=C(SiMe3)2 (3) + MX exists.Thereby, silaethene 3 is formed in Et2O at -78 deg C (X/M = Br/Li) or at room temperature (X/M = F/Li, Br/Na), respectively, reversibly in low concentrations and at higher temperatures irreversibly (formation of secondary products of 3).The intermediacy of 3 has been established chemically by trapping 3 with (for example) RLi (formation of insertion products in the R-Li bond), Ph2C=NSiMe3 (formation of a cycloadduct, which may serve as a source of 3), tBu2MeSiN3 (formation of a cycloadduct), and particularly 2,3-dimethyl-1,3-butadiene (formation of Diels-Alder and ene reaction products).In the last case products and yields are independent of the origin of 3.From Me2Si=C(SiMe3)2 (1) to 3 there is only a gradual (but no principal) change of silaethene reactivity (3 is more Lewis acidic than 1). - Keywords: Silaethenes/ Bromotris(silyl)methane derivatives
- Wiberg, Nils,Link, Matthias,Fischer, Gerd
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p. 409 - 418
(2007/10/02)
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