- Photoinduced reductive coupling of organochlorosilanes with SmI2/Sm
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We report efficient reductive dimerization of chlorosilanes with SmI2/Sm in 1,2-dimethoxyethane upon visible light irradiation. This procedure can be applied to the synthesis of polysilanes from dichlorosilanes. The molecular weight of the obtained polysilanes was higher and their molecular weight distribution was narrower than the polysilanes produced by reactions with SmI2/Sm in dark.
- Yoshimura, Aya,Tomisaka, Yuri,Li, Zhifang,Nomoto, Akihiro,Ogawa, Akiya
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- Bissilyl ketone; A convenient method for the synthesis and its Pd(0) catalyzed reaction with alkenes and alkynes
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A convenient method for the preparation of a bissilyl ketone is developed via a bissilyl ketone acetal as its precursor. The bissilyl ketone reacts with electron deficient alkynes and alkenes in the presence of Pd(0) catalyst to give bis-silylated products.
- Sakurai, Hidehiro,Yamane, Motoki,Iwata, Masahiro,Saito, Nobuo,Narasaka, Koichi
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- Electrolytic Behavior of Iodo- and Chlorosilanes. The Formation of Si-Si and Si-sp-C Bonds
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Electrolysis of iodosilanes with Al/Pt electrodes in pivalonitrile results in the formation of the Si-Si bonds to give the corresponding disilanes.On the other hand, the electrolysis of various halosilanes such iodo-, chloro-, and fluorosilanes with Pt/Pt electrodes in the presence of phenylacetylene leads to the formation of the Si-sp-carbon bonds to give phenylethynylated products.
- Kunai, Atsutaka,Ohnishi, Osamu,Sakurai, Tomohiro,Ishikawa, Mitsuo
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- Direct construction of silicon-silicon bond by using the low-valent titanium reagent
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The reductive dimerization or polymerization of organochlorosilanes has been achieved by using the low-valent titanium reducing agent other than the alkali metals that are invariable used in the Wurtz-type coupling reaction. Applying this method, the corresponding disilanes or poly(methylvinylsilane) was obtained in good yields. The poly(methylvinylsilane) synthesized by this method is highly pure with a high molecular weight and a narrow molecular weight distribution (Mw/Mn = 1.6, Mn = 16,860).
- Lai, Guoqiao,Li, Zhifang,Huang, Jiabang,Jiang, Jianxiong,Qiu, Huayu,Shen, Yongjia
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- Reductive Elimination of sym-Diphenyltetramethyldisilane from cis-Bis(phenyldimethylsilyl)bis(phosphine)platinum(II) Complexes
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Reductive elimination of cis-bis(phenyldimethylsilyl)bis(phosphine)platinum(II) complexes was found to occur to give sym-diphenyltetramethyldisilane together with redistribution by-products.Addition of free phosphine was favorable for the reductive elimin
- Kobayashi, Toshi-aki,Hayashi, Teruyuki,Yamashita, Hiroshi,Tanaka, Masato
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- Proximity enforced oxidative addition of a strong unpolar σ-Si-Si bond at rhodium(i)
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The new bidentate bisphosphino ligand (5-Ph2P-Ace-6-SiMe2)2 (1) binds rhodium(i) chloride and brings it into close proximity to a strong unpolar σ-Si-Si bond, in which it immediately inserts. In the spirocyclic Rh(iii) product of the oxidative addition, (5-Ph2P-Ace-6-SiMe2)2RhCl (2), the two Si atoms are still close enough to engage in weak non-covalent interactions.
- Beckmann, Jens,Holsten, Sebastian,Hupf, Emanuel,Lork, Enno,Mebs, Stefan
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- Electroreductive Formation of Polysilanes
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Electroreduction of dichlorosilanes, such as 1,1-dichlorodialkylsilanes, 1,2-dichlorotetra-alkyldisilanes, and 1,4-bis(chlorodialkylsilyl)benzenes, with Mg electrodes in a single-compartment cell was found to yield the corresponding polysilanes.
- Shono, Tatsuya,Kashimura, Shigenori,Ishifune, Manabu,Nishida, Ryoichi
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- Generation and characterization of 1,2-Diaryl-1,1,2,2-tetramethyldisilane cation radicals
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Nanosecond laser flash photolysis methods were used to generate and spectrally characterize the cation radicals of 1,2-diaryl-1,1,2,2,- tetramethyldisilanes (Ar = p-X-Ph, X = H, CH3, OCH3) in hexafluoroisopropanol (HFIP) at room temperature. The disilane cation radicals rapidly reacted with methanol, with bimolecular rate constants ranging from 0.63 to 2.1 ×108 M-1 s-1. The cation radicals were found to react with tert-butanol 4-5 times more slowly than methanol, consistent with a small steric effect for nucleophile-assisted fragmentation of the Si-Si bond. The standard potentials for oxidation of the disilanes in HFIP were determined by two different methods: first, by measuring equilibrium constants for electron exchange between the disilanes and the cation radical of hexaethylbenzene and, second, by combining electrochemical data from cyclic voltammetry with the lifetimes of the disilane cation radicals measured by laser flash photolysis in the same media. Agreement between the two methods was excellent (≤3 mV). The oxidation of 1,2-di-p-methoxyphenyl-1,1,2,2,- tetramethyldisilane by slow scan cyclic voltammetry in acetonitrile was not found to be reversible, in contrast to prior literature reports. Possible explanations for the prior results are proposed.
- Guirado, Gonzalo,Haze, Olesya,Dinnocenzo, Joseph P.
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- Electrochemical Oxidation of Hydrosilanes. A Synthetic Approach to Halosilanes and Disilanes
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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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- ALLYLSILANES FROM ALLYLCHLORIDES AND SILYLCUPRATES
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The beneficial effects of copper (I) salts on the reactions of cyclohex-2-enyl chlorides and 3,4-epoxycyclohexene with phenyldimethylsilyllithium are reported.
- Laycock, Bronwyn,Kitching, William,Wickham, Geoffrey
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- Reactions of molybdenum hydrides with organochlorosilanes: Silicon-silicon bond formation under mild conditions
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Reactions of molybdenum hydrides containing polydentate phosphinoalkylsilyl ligands with a number of chlorosilanes have been investigated; this has led to the discovery of a novel type of a dechlorinative Si-Si coupling reaction.
- Asaeda, Takahiro,Lee, Joo Yeon,Watanabe, Kyosuke,Minato, Makoto
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- SILYL-TITANATION OF ACETYLENES AND 1,3-DIENES
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A TiIII-Si active species, Cp2TiSiMe2Ph, is formed either by the reaction of Cp2TiCl2 with two equivalents of PhMe2SiLi or by the reaction of Cp2TiCl with one equivalent of PhMe2SiLi.Highly regio- and stereo-selective silyltitanation by this species has been observed with acetylenes and 1,3-dienes.
- Tamao, Kohei,Akita, Munetaka,Kanatani, Ryuichiro,Ishida, Neyoshi,Kumada, Makoto
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- Tunable SiN Hybrid Conjugated Materials
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We report the synthesis of a family of N-aryl cyclosilazanes. The reaction of 1,2-bis(trifluoromethanesulfonate)tetramethyldisilane with para-substituted anilines gives six-membered rings with no observed condensation polymerization. X-ray crystallography
- Folster, Carlton P.,Nguyen, Phi N.,Siegler, Maxime A.,Klausen, Rebekka S.
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- The phenyldimethylsilyllithium reagent
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The phenyldimethylsilyllithium reagent can be titrated using the double titration for organolithium reagents, in spite of the formation of silyl bromide on adding dibromoethane; the reagent is different from alkyllithiums in maintaining its titre over a l
- Fleming, Ian,Roberts, Richard S.,Smith, Stephen C.
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- Copper-Catalyzed Cross-Coupling of Silicon Pronucleophiles with Unactivated Alkyl Electrophiles Coupled with Radical Cyclization
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A copper-catalyzed C(sp3)-Si cross-coupling of aliphatic C(sp3)-I electrophiles using a Si-B reagent as the silicon pronucleophile is reported. The reaction involves an alkyl radical intermediate that also engages in 5-exo-trig ring closures onto pendant alkenes prior to the terminating C(sp3)-Si bond formation. Several Ueno-Stork-type precursors cyclized with excellent diastereocontrol in good yields. The base-mediated release of the silicon nucleophile and the copper-catalyzed radical process are analyzed by quantum-chemical calculations, leading to a full mechanistic picture.
- Xue, Weichao,Qu, Zheng-Wang,Grimme, Stefan,Oestreich, Martin
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- A nickel-catalyzed silylation reaction of alkyl aryl sulfoxides with silylzinc reagents
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Ni(PEt3)Cl2-catalyzed silylation of alkyl aryl sulfoxides with silylzinc reagents was carried out. This protocol allows alkyl aryl sulfoxides to convert to arylsilicon compounds under mild reaction conditions, tolerates a range of functional groups and is suitable for a wide scope of substrates.
- Li, Wei-Ze,Wang, Zhong-Xia
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supporting information
p. 5082 - 5086
(2021/06/21)
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- Disilane and preparation method thereof
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The invention discloses disilane and a preparation method thereof. The preparation method of disilane includes: subjecting a uniformly mixed reaction system containing tertiary hydrosilane and a catalyst to dehydrogenation reaction at a temperature ranging from -10DEG C to 120DEG C to obtain disilane, wherein the catalyst comprises a silver salt. The invention also discloses the disilane preparedby the method. The method for preparation of the disilane by catalyzing tertiary silane dehydrogenation with the silver salt adopts the silver salt to activate the Si-H bond in the silane so as to realize construction of disilane. Therefore, the invention provides an efficient and simple method for preparation of the compound, and the application prospect is wide.
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Paragraph 0035-0038; 0078-0081
(2020/01/25)
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- A Strategy for Accessing Aldehydes via Palladium-Catalyzed C?O/C?N Bond Cleavage in the Presence of Hydrosilanes
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We report the catalytic reduction of both active esters and amides by selective C(acyl)?X (X=O, N) cleavage to access aldehyde functionality via a palladium-catalyzed strategy. Reactions are promoted by hydrosilanes as reducing reagents with good to excellent yields and with excellent chemoselectivity for C(acyl)?N and C(acyl)?O bond cleavage. Carboxylic acid C(acyl)?O bonds are activated by 2-chloro-4,6-dimethoxy-1,3,5-triazine (CDMT) to form triazine ester intermediates, which further react with hydrosilanes to yield aldehydes in one-pot two-step procedures. We demonstrate that C(acyl)?O cleavage/formylation offers higher yields and broader substrate scopes compared with C(acyl)?N cleavage under the same reaction conditions.
- He, Zhanyu,Liu, Tingting,Ru, Junxiang,Wang, Yulin,Wang, Zijia,Zeng, Zhuo
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supporting information
p. 5794 - 5800
(2020/12/01)
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- METHOD FOR PRODUCING SILYL SODIUM COMPOUND AND METHOD FOR DEOXIDIZING EPOXY COMPOUND
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PROBLEM TO BE SOLVED: To construct a technique which can simply, efficiently and inexpensively synthesize a silyl sodium compound in a small number of processes and in a short time, especially to construct a technique which synthesizes a silyl sodium compound by using easily available reagents from a viewpoint of sustainability without using reagents which are difficult to handle and are toxic. SOLUTION: There is provided a method for synthesizing a silyl sodium compound comprising a step of reacting a dispersion obtained by dispersing a silyl halide compound or a disilane compound with sodium into a dispersion solvent, the silyl halide compound or the disilane compound as a starting compound, in a reaction solvent to obtain the silyl sodium compound. There is also provided a method for deoxidizing an epoxy compound comprising a step of reacting the silyl sodium compound obtained by synthesizing method of the silyl sodium compound with an epoxy compound to deoxidize the epoxy compound to stereoselectively produce an alkene compound. SELECTED DRAWING: Figure 1 COPYRIGHT: (C)2020,JPOandINPIT
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Paragraph 0090-0092
(2020/05/06)
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- Aryl–Aryl Interactions in (Aryl-Perhalogenated) 1,2-Diaryldisilanes
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Three 1,2-diaryltetramethyldisilanes X5C6-(SiMe2)2-C6X5 with two C6H5, C6F5, or C6Cl5 groups were studied concerning the im
- Linnemannst?ns, Marvin,Schwabedissen, Jan,Neumann, Beate,Stammler, Hans-Georg,Berger, Raphael J. F.,Mitzel, Norbert W.
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supporting information
p. 2169 - 2173
(2020/02/11)
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- Visible-Light-Initiated Manganese-Catalyzed E-Selective Hydrosilylation and Hydrogermylation of Alkynes
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Manganese-photocatalyzed activation of the Si-H bond in silanes for the hydrosilylation of alkynes has been developed. The mild protocol operates efficiently with high regioselectivity (anti-Markovnikov) and stereoselectivity (Z/E ratio ranges from 92:8 to >99:1), providing a wide range of Z-vinylsilanes in high yields. Moreover, visible-light-induced manganese-catalyzed activation of the Ge-H bond for E-selective alkyne hydrogermylation is reported for the first time.
- Liang, Hao,Ji, Yun-Xing,Wang, Rui-Han,Zhang, Zhi-Hao,Zhang, Bo
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supporting information
p. 2750 - 2754
(2019/04/30)
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- Nickel-catalyzed cross-coupling reaction of carbamates with silylmagnesium reagents
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The C–O bonds are kinetically inert in cross-coupling reactions compared to those of carbon–halogen bonds. Thus, developing methodologies for the activation of C–O bonds in cross-coupling reactions remains a major challenge. We disclose an unprecedented nickel mediated cross-coupling of carbamates with silylmagnesium reagents that does not require the expensive silylboranes. Silylmagnesium reagents were prepared from either silyllithium or silyl iodides. This methodology is distinguished by the synthesis of trimethylsilyl coupled product and its synthetic applications. Kinetic studies and radical clock experiments revealed the rate-limiting C–O bond cleavage, half order with respect to the catalyst and a non-radical transition state.
- Murugesan, Vetrivelan,Balakrishnan, Venkadesh,Rasappan, Ramesh
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p. 293 - 298
(2019/08/12)
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- Method for continuously preparing disilane compounds by micro-reaction device
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The invention discloses a method for continuously preparing disilane compounds by a micro-reaction device. The method comprises the following steps: (1) a solution A is prepared from organosilane by dissolving in a first organic solvent, or is organosilane; (2) a solution B is prepared from an oxidant by dissolving in a second organic solvent, or is an oxidant; (3) the solution A and the solutionB are pumped into a micro-mixer of the micro-reaction device simultaneously for mixing, a product then flows into a microreactor of the micro-reaction device for reaction, and the disilane compounds are prepared, wherein the microreactor is filled with a catalyst. Raw materials required in the method are easily available and have better stability, metal copper compounds are used as a catalyst forcoupling reaction on trisubstituted silanes, and the coupling effect on trisubstituted silanes is better than that of alkali metal catalysts and transition metal catalysts; a micro-channel reactor issuitable for an exothermic coupling reaction due to good mixing and heat transfer performance.
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Paragraph 0025; 0026; 0033; 0034
(2018/05/16)
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- Formal Nucleophilic Silyl Substitution of Aryl Halides with Silyllithium Reagents via Halogenophilic Attack of Silyl Nucleophiles
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A new reaction has been developed for the formal nucleophilic silyl substitution of aryl halides with silyllithium or silylpotassium reagents. Dimethylphenylsilyllithium reacted with various aryl halides to form the corresponding arylsilanes in moderate to good yields with concomitant formation of the disilanes under the optimized reaction conditions. Mechanistic studies indicated that this silyl substitution reaction progresses through polar halogenophilic attack of silyl nucleophiles.
- Yamamoto, Eiji,Ukigai, Satoshi,Ito, Hajime
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p. 2460 - 2464
(2017/10/06)
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- Silylative cyclopropanation of allyl phosphates with silylboronates
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A potassium-bis(trimethylsilyl)amide-mediated cyclopropanation of allyl phosphates with silylboronates has been developed. Unlike the reported copper-catalyzed allylic substitution reactions, the nucleophile selectively attacks at the β-position of the allylic substrates under the present reaction conditions. The mechanism of this process has also been investigated, thus indicating the involvement of a silylpotassium species as the active nucleophilic component.
- Shintani, Ryo,Fujie, Ryuhei,Takeda, Momotaro,Nozaki, Kyoko
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supporting information
p. 6546 - 6549
(2014/06/24)
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- On the reactivity of silylboranes toward lewis bases: Heterolytic B-Si cleavage vs. adduct formation
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Silylboranes are important reagents in a variety of catalytic silylation and silaboration reactions. While transition-metal-catalyzed reactions are well established, organo-/Lewis base-catalyzed reactions of silylboranes have only recently emerged. For both catalytic processes the reactivity of silylboranes toward Lewis bases is of relevance. While for organo-catalyzed reactions Lewis base activation of the silylborane has been proposed, transition-metal- and especially copper-catalyzed reactions also frequently require the presence of Lewis basic alkali metal alkoxides. In the present study we explore the reaction of K(18-crown-6) tert-butoxide and the NHC 1,3-diisopropyl-4,5-dimethyl- imidazol-2-ylidene as exemplary Lewis bases with the two silylboranes pinB-SiMe2Ph and pinB-SiPh3 (pin = OCMe 2CMe2O). The reaction with K(18-crown-6) tert-butoxide results in activation of the boron-silicon bond. The isolated product of this activation is either the potassium silyl complex [K(18-crown-6)SiPh3] or [K(18-crown-6)(thf)2][pinB(SiMe2Ph)2], the formal Lewis acid/base adduct of [K(18-crown-6)SiMe2Ph] with pinB-SiMe2Ph. Both complexes react essentially as sources of nucleophilic silyl moieties in reactions with exemplary electrophiles. In contrast, usage of the carbene leads to the formation of isolable Lewis acid/base adducts of the type (NHC)pinB-SiR3, which do not react as sources of nucleophilic silyl moieties. The identification and characterization of these species appears of relevance for the mechanistic understanding and further development of Lewis base/organo- as well as transition-metal-catalyzed silyl transfer reactions. Copyright
- Kleeberg, Christian,Borner, Corinna
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p. 2799 - 2806
(2013/07/11)
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- Epoxidation of 4-alkylidenecyclopentenones: A route to the 1-oxaspiro[2.4]hept-6-en-5-one framework
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Thanks to their lack of polarity, the exocyclic double bonds of 4-alkylidenecyclopentenones 4 are selectively epoxidized by MCPBA to give spiroepoxycyclopentenones 7, which feature the nonclassical 1-oxaspiro[2.4]hept- 6-en-5-one framework. Under acidic c
- Ahmar, Mohammed,Thome, Stephane,Cazes, Bernard
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p. 7093 - 7105
(2013/02/23)
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- Conductive molecular silicon
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Bulk silicon, the bedrock of information technology, consists of the deceptively simple electronic structure of just Si-Si σ bonds. Diamond has the same lattice structure as silicon, yet the two materials have dramatically different electronic properties. Here we report the specific synthesis and electrical characterization of a class of molecules, oligosilanes, that contain strongly interacting Si-Si σ bonds, the essential components of the bulk semiconductor. We used the scanning tunneling microscope-based break-junction technique to compare the single-molecule conductance of these oligosilanes to those of alkanes. We found that the molecular conductance decreases exponentially with increasing chain length with a decay constant β = 0.27 ± 0.01 A-1, comparable to that of a conjugated chain of C = C π bonds. This result demonstrates the profound implications of σ conjugation for the conductivity of silicon.
- Klausen, Rebekka S.,Widawsky, Jonathan R.,Steigerwald, Michael L.,Venkataraman, Latha,Nuckolls, Colin
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supporting information; experimental part
p. 4541 - 4544
(2012/04/23)
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- Facile synthesis of hypersilylated aromatic compounds by palladium-mediated arylation reaction
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The treatment of aryl iodides with tris(trimethylsilyl)silane in the presence of Pd(P(tBu)3)2 and the Huenig base leads to the formation of hypersilylated aromatic products in good to excellent yields without cleavage of weak Si-Si b
- Lesbani, Aldes,Kondo, Hitoshi,Sato, Jun-Ichi,Yamanoi, Yoshinori,Nishihara, Hiroshi
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scheme or table
p. 7784 - 7786
(2010/12/19)
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- PREPARATION OF SI-SI BOND-BEARING COMPOUNDS
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Si—Si bond-bearing compounds are effectively prepared by irradiating with radiation or heating Si—H group-bearing silicon compounds in organic solvents in the presence of iron complex catalysts. The Si—Si bond-bearing compounds are useful as a base material in photoresist compositions, ceramic precursor compositions, and conductive compositions.
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Page/Page column 2-3
(2009/05/28)
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- Catalytic and stoichiometric reactions of tertiary silanes with [Ir(Me)2Cp*L] (Cp=η5-C5Me5; L=PMe3, PMe2Ph, PMePh2, PPh3) in the presence of one-electron oxidants. A unique case of Si-H, Si-C, Ir-C and P-F bonds one-step activation: Crystal structure of [Ir(Ph)(SiPh2F)Cp*(PMe3)]
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The iridium(III) dimethyl derivatives [Ir(Me)2Cp*L] (Cp=η5-C5Me5; L=PMe3 1a, PPh3 1d) catalyze the dehydrogenative coupling of dimethylphenylsilane in the presence of one-electron oxidants to yield Me2PhSiSiPhMe2. Compounds 1a-d react with triphenylsilane in the presence of [FeCp2]PF6 to give methane and [Ir(Ph)(SiFPh2)Cp*L] (L=PMe3 (2a), PMe2Ph (2b), PMePh2 (2c), PPh3 (2d)). 2a was structurally characterized by single-crystal X-ray diffraction experiments. The `three-legged piano stool' coordination polyhedron is slightly deformed.
- Diversi, Pietro,Marchetti, Fabio,Ermini, Valentina,Matteoni, Simona
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p. 154 - 160
(2007/10/03)
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- Electroreductive Synthesis of Polysilanes, Polygermanes, and Related Polymers with Magnesium Electrodes
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The electroreduction of alkylaryldichlorosilane carried out with Mg cathode and anode in a single compartment cell gave high molecular weight poly(alkylarylsilane) (Mn = 5200-31000, Mw/Mn = 1.4-1.8) in 5-79% yield. The effects of electrode material, monomer concentration, amount of supplied electricity, and ultrasound were investigated. This electroreductive method was also successfully applied to the synthesis of polygermanes, silane-geramane copolymers, and also poly[p-(disilanylene)phenylenes].
- Kashimura, Shigenori,Ishifune, Manabu,Yamashita, Natsuki,Bu, Hang-Bom,Takebayashi, Masakatsu,Kitajima, Satsuki,Yoshiwara, Daisuke,Kataoka, Yasuki,Nishida, Ryoichi,Kawasaki, Shin-Ichi,Murase, Hiroaki,Shono, Tatsuya
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p. 6615 - 6621
(2007/10/03)
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- The preparation and analysis of the phenyldimethylsilyllithium reagent and its reaction with silyl enol ethers
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Phenyldimethylsilyllithium is formed from lithium and phenyldimethylsilyl chloride by slow cleavage of the Si-Si bond of 1,1,2,2-tetramethyl-1,2-diphenyldisilane after the rapid formation of the disilane. 1,1,2,2-Tetramethyl-1,2-diphenyldisiloxane, produced from the silyl chloride by reaction with oxides and hydroxides on the lithium metal surface, is cleaved by dimethyl(phenyl)silyllithium to give lithium dimethyl(phenyl)silanoxide. Dimethyl(phenyl)silyllithium reacts with 1,2-dibromoethane to give dimethyl(phenyl)silyl bromide, which is so rapidly consumed by excess silyllithium reagent that it does not interfere with the double titration used to measure its concentration. Dimethyl(phenyl)silane, produced by protonation of the silyllithium reagent, is also consumed by the silyllithium reagent to give 1,1,2,2-tetramethyl-1,2-diphenyldisilane, which regenerates the silyllithium reagent, as long as lithium is still present. By-products in the preparation of dimethyl(phenyl)silyllithium include 1,3-diphenyl-1,1,2,2,3,3-hexamethyltrisilane, dimethyldiphenylsilane and 1,4-bis[dimethyl(phenyl)-silyl]benzene. Dimethyl(phenyl)silyllithium displaces the silyl group from the tert-butyldimethylsilyl enol ether of cyclohexanone to give the lithium enolate under relatively mild conditions.
- Fleming, Ian,Roberts, Richard S.,Smith, Stephen C.
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p. 1209 - 1214
(2007/10/03)
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- Method for producing disilanes
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A method for producing disilane characterized in that halosilane is subjected to electrochemical reaction using Al, Al alloy, Mg, Mg alloy, Cu, Cu alloy, Zn or Zn alloy as anode, a lithium salt as supporting electrolyte, an Al salt, Fe salt, Mg salt, Zn salt, Sn salt, Co salt, Pd salt, V salt, Cu salt, Ca salt, Na salt or K salt as current carrying aid, and an aprotic solvent as solvent, thereby producing disilane.
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- Dearylation of α,ω-diphenylpermethylated oligosilanes with triflic acid
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The relative rates of displacement of phenyl groups for a series of α,ω-diphenylpermethylated oligosilanes with the formula Ph(SiMe2)nPh (n = 2-5) were studied.Triflic acid was utilized in the displacement reactions which occur as a two-step process with protonation at the ipso-carbon atom as the rate limiting step.The results showed the displacement of the first phenyl group is more facile than the second group.The largest difference in reactivities is found for the disilane.Competitive displacement reactions between various oligomers were analyzed to establish the influence of the chain length of oligosilanes on the relative reactivities of the terminal phenyl groups.Both the first and second phenyl group displacement reactions are faster for the longer chain oligomers than the shorter analogs.The 13C NMR spectra of the oligosilanes indicate the highest electron density on the ipso-carbon atoms in the disilane, in contrast to its lowest reactivity.This is interpreted by the increased stabilization of the positive charge in the transition state with an increase in the chain length.Thus, the reactivities of oligosilanes are governed by the structures of the transition states rather than the ground states.
- Ruehl, Karen E.,Matyjaszewski, Krzysztof
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- Reactivity of cis-Bis(dimethylphenylsilyl)bis(phosphine)platinum Complexes toward Unsaturated Compounds Relevant to Double Silylation
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The reaction of phenylacetylene, tolane, or isoprene with cis-bis(dimethylphenylsilyl)bis(methyldiphenylphosphine)platinum readily took place to result in 1,2- or 1,4- double silylation, respectively.Ethylene also underwent double silylation with the platinum complex, but styrene selectively gave E-2-(dimethylphenylsilyl)styrene.
- Kobayashi, Toshi-aki,Hayashi, Teruyuki,Yamashita, Hiroshi,Tanaka, Masato
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p. 467 - 470
(2007/10/02)
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- Efficient formation and cleavage of disilanes by potassium-graphite. Silylation with silyl metal reagents
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Potassium-graphite laminate (C8K) very rapidly forms disilanes from chlorosilanes and then rapidly cleaves the disilanes to give silyl potassium reagents which can be converted into potassium silyl cuprates, -manganates, and -vanadates that are useful for various nucleophilic substitution and addition reactions.
- Fuerstner, Alois,Weidmann, Hans
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- Laser Photolysis and CIDEP Studies of the Formation of Phenyl-Substituted Group 4B Element (Silicon, Germanium, and Tin)-Centered Radicals in Direct Photoejection of the Group 4B Element-Centered Anions
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Phenyl-substituted group 4B element-centered radicals generated by the direct photoejection from the group 4B element-centered anions were observed by laser photolysis at room temperature.In order to claify the mechanism of this process, CIDEP study of the photolysis of the group 4B element-centered anions was carried out at 77 and 4.2 K.From the emissive patterns observed for the germyl and stannyl anions after the excitation by a pluse laser, the photoejection reactions were most probably considered to occur from triplet anions.
- Mochida, Kunio,Wakasa, Masanobu,Sakaguchi, Yoshio,Hayashi, Hisaharu
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p. 7942 - 7947
(2007/10/02)
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- Effects of 16-Heterosubstitution on the Regiochemistry of the D-Homo Rearrangement
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The 16β-phenylthio-, 16β-phenylseleno-, and 16β-dimethylphenylsilyl-substituted 3β,17α-dihydroxy-5-pregnen-20-ones have been prepared by nucleophilic ring opening of 16α,17α-epoxysteroids in order to study the influence of the 16-substituent on the regioc
- Bischofberger, Norbert,Walker, Keith A. M.
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p. 3604 - 3609
(2007/10/02)
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