- CMe3SiX3 and SiMe3SiX3 (X = H, F, Cl, Br, I): A combined ab initio and vibrational spectroscopic study
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The infrared and Raman vibrational spectra of the tert-butylsilanes CMe3SiX3 and disilanes SiMe3SiX3 (X = H, F, Cl, Br, I) have been measured and assigned with the help of normal coordinate analyses and potential energy distribution analyses employing ab initio optimized geometries and ab initio symmetry force constants. Scaled theoretical SiX and SiSi force constants are smaller than values estimated by extrapolation from spectroscopic force constants of related disilanes. The synthesis of the novel compound SiMe3SiI3 and the residual disilanes SiMe3SiX3 (X = H, F, Cl, Br) is described.
- Zink, Robert,Hassler, Karl
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- Preparation of oligosilanes containing perhalogenated silyl groups (-SiX3, -SiX2-, >SiX-, X = Cl, Br) and their hydrogenation by stannanes
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Starting from methylphenylsubstituted oligosilanes the disilanes SiX3-SiXi,Me3-i (i = 0, 1, 2; X = Cl, Br), trisilanes SiX2(SiXiMe3-i) (i = 0, 1) and branched tetrasilanes SiX(SiXMe2)3 were synthesized and their behavior towards the Lewis-base catalyzed hydrogenation by stannanes was investigated. In the case of methylchlorodisilanes SiCl3-SiCliMe3-i Si-Si bond cleavage competes with the hydrogenation reaction.
- Herzog,Roewer
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p. 217 - 223
(2007/10/03)
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- Catalytic asymmetric synthesis of β-hydroxy ketones by palladium-catalyzed asymmetric 1,4-disilylation of α,β-unsaturated ketones
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1,4-Disilylation of β,β-unsaturated ketones with 1,1-dichloro-1-phenyl-2,2,2-trimethyldisilane proceeded in the presence of phosphine-palladium catalysts in benzene. High enantio-selectivity (up to 92%) was observed in the disilylation with dichloro[(R)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl] palladium(II) as a catalyst (0.5 mol %). The disilylation products, 1-(trimethyisilyloxy)-3-(dichlorophenylsilyl)propenes, were readily converted into optically active α-unsubstituted or anti α-substituted β-(phenyldimethylsilyl) ketones, the oxidation of which gave the corresponding optically active β-hydroxy ketones in high yields.
- Matsumoto, Yonetatsu,Hayashi, Tamio,Ito, Yoshihiko
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p. 335 - 346
(2007/10/02)
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- The synthesis of novel chlorosilyl and chlorogermyl mercurials with some of their chemical reactions
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When a mercury alkyl is irradiated in the presence of trichlorosilane, bis(trichlorosilyl)mercury, a white crystalline solid, and the alkane are formed. In a similar reaction with methyldichlorosilane, bis(methyldichlorosilyl)mercury is a product. With trichlorogermane as a reactant a similar light-induced reaction produces bis(trichlorogermyl)mercury. These novel mercurials react with compounds possessing a silicon-hydrogen bond to form disilanes. Preparations are described for methylpentachlorodisilane, 1,1-dimethyltetrachlorodisilane, 1,2-dimethyltetrachlorodisilane, 1,1,1,-trimethyltrichlorodisilane, 1,1,2-trimethyltrichlorodisilane, 1,1,1,2-tetramethyldichlorodisilane, 1,1,2,2-tetramethyldichlorodisilane, pentamethylchlorodisilane, trichlorosilyltrichlorogermane, and trimethylsilylmethyltrichlorogermane using various modifications of this reaction. Syntheses have been devised for the mercurials, bis(trichlorosilyl)mercury, bis(methyldichlorosilyl)mercury, bis(trichlorogermyl)mercury, and (trimethylsilylmethyl)trichlorogermylmercury. Bis(dimethylchlorosilyl)mercury is formed at low temperatures but decomposes at temperatures above -79°. Bis(trichlorosilyl)mercury also reacts with dimanganese decacarbonyl to form trichlorosilylmanganese pentacarbonyl.
- Bettler, Charles R.,Sendra, Joseph C.,Urry, Grant
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p. 1060 - 1065
(2007/10/05)
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