776-76-1Relevant academic research and scientific papers
Organocalcium Complex-Catalyzed Selective Redistribution of ArSiH3or Ar(alkyl)SiH2to Ar3SiH or Ar2(alkyl)SiH
Li, Tao,McCabe, Karl N.,Maron, Laurent,Leng, Xuebing,Chen, Yaofeng
, p. 6348 - 6356 (2021/05/29)
Calcium is an abundant, biocompatible, and environmentally friendly element. The use of organocalcium complexes as catalysts in organic synthesis has had some breakthroughs recently, but the reported reaction types remain limited. On the other hand, hydrosilanes are highly important reagents in organic and polymer syntheses, and redistribution of hydrosilanes through C-Si and Si-H bond cleavage and reformation provides a straightforward strategy to diversify the scope of such compounds. Herein, we report the synthesis and structural characterization of two calcium alkyl complexes supported by β-diketiminato-based tetradentate ligands. These two calcium alkyl complexes react with PhSiH3 to generate calcium hydrido complexes, and the stability of the hydrido complexes depends on the supporting ligands. One calcium alkyl complex efficiently catalyzes the selective redistribution of ArSiH3 or Ar(alkyl)SiH2 to Ar3SiH and SiH4 or Ar2(alkyl)SiH and alkylSiH3, respectively. More significantly, this calcium alkyl complex also catalyzes the cross-coupling between the electron-withdrawing substituted Ar(R)SiH2 and the electron-donating substituted Ar′(R)SiH2, producing ArAr′(alkyl)SiH in good yields. The synthesized ArAr′(alkyl)SiH can be readily transferred to other organosilicon compounds such as ArAr′(alkyl)SiX (where X = OH, OEt, NEt2, and CH2SiMe3). DFT investigations are carried out to shed light on the mechanistic aspects of the redistribution of Ph(Me)SiH2 to Ph2(Me)SiH and reveal the low activation barriers (17-19 kcal/mol) in the catalytic reaction.
Selective C-O Bond Reduction and Borylation of Aryl Ethers Catalyzed by a Rhodium-Aluminum Heterobimetallic Complex
Hara, Naofumi,Nakao, Yoshiaki,Saito, Teruhiko,Seki, Rin
, p. 6388 - 6394 (2021/05/31)
We report the catalytic reduction of a C-O bond and the borylation by a rhodium complex bearing an X-Type PAlP pincer ligand. We have revealed the reaction mechanism based on the characterization of the reaction intermediate and deuterium-labeling experiments. Notably, this novel catalytic system shows steric-hindrance-dependent chemoselectivity that is distinct from conventional Ni-based catalysts and suggests a new strategy for selective C-O bond activation by heterobimetallic catalysis.
METHOD FOR PRODUCING SILYL SODIUM COMPOUND AND METHOD FOR DEOXIDIZING EPOXY COMPOUND
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Paragraph 0081-0083, (2020/05/06)
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
Synthesis of hydrosilanes: Via Lewis-base-catalysed reduction of alkoxy silanes with NaBH4
Aoyagi, Keiya,Ohmori, Yu,Inomata, Koya,Matsumoto, Kazuhiro,Shimada, Shigeru,Sato, Kazuhiko,Nakajima, Yumiko
supporting information, p. 5859 - 5862 (2019/05/27)
Hydrosilanes were synthesized by reduction of alkoxy silanes with BH3 in the presence of hexamethylphosphoric triamide (HMPA) as a Lewis-base catalyst. The reaction was also achieved using an inexpensive and easily handled hydride source NaBH4, which reacted with EtBr as a sacrificial reagent to form BH3in situ.
A silicon hydrogenation for the preparation of compounds
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Paragraph 0030; 0031; 0032; 0033, (2018/03/09)
The invention relates to a method for preparing silicon hydrides. Under the protection of Ar gas, THF and/or HMPA are/is used as a solvent, chlorosilane or derivatives of chlorosilane reacts with magnesium metal to prepare the silicon hydrides. The method has the characteristics of being cheap in raw materials, easy to get the raw materials, easy to operate, mild in reaction conditions and low in cost.
Hydrosilane synthesis via catalytic hydrogenolysis of halosilanes using a metal-ligand bifunctional iridium catalyst
Beppu, Teruo,Sakamoto, Kei,Nakajima, Yumiko,Matsumoto, Kazuhiro,Sato, Kazuhiko,Shimada, Shigeru
, p. 75 - 80 (2018/06/20)
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.
Hydrogenation of chlorosilanes by NaBH4
Ito, Masaki,Itazaki, Masumi,Abe, Takashi,Nakazawa, Hiroshi
, p. 1434 - 1436 (2016/12/03)
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.
Iridium Pincer Catalysts for Silane Dehydrocoupling: Ligand Effects on Selectivity and Activity
Mucha, Neil T.,Waterman, Rory
supporting information, p. 3865 - 3872 (2015/08/19)
Catalytic reactions of bisphosphinite pincer-ligated iridium compounds p-XR(POCOP)IrHCl (POCOP) [2,6-(R2PO)2C6H3, R = iPr, X = H (1); R = tBu, X = COOMe (2); = H (3); = NMe2 (4)] with primary and secondary silanes have been performed. Complex 1 is primarily a silane redistribution precatalyst, but dehydrocoupling catalysis is observed for sterically demanding silane substrates or with aggressive removal of H2. The bulkier compounds (2-4) are silane dehydrocoupling precatalysts that also undergo competitive redistribution with less hindered substrates. Products generated from reactions utilizing 2-4 include low molecular weight oligosilanes with varying degrees of redistribution present or disilanes when employing more sterically demanding silane substrates. Selectivity for redistribution versus dehydrocoupling depends on the steric and electronic environment of the metal but can also be affected by reaction conditions. (Chemical Equation Presented).
Si-H bond activation at {(NHC)2Ni0} leading to hydrido silyl and bis(silyl) complexes: A versatile tool for catalytic Si-H/D exchange, acceptorless dehydrogenative coupling of hydrosilanes, and hydrogenation of disilanes to hydrosilanes
Schmidt, David,Zell, Thomas,Schaub, Thomas,Radius, Udo
supporting information, p. 10816 - 10827 (2014/07/08)
The unique reactivity of the nickel(0) complex [Ni2(iPr 2Im)4(COD)] (1) (iPr2Im = 1,3-di-isopropyl- imidazolin-2-ylidene) towards hydrosilanes in stoichiometric and catalytic reactions is reported. A series of nickel hydrido silyl complexes cis-[Ni(iPr2Im)2(H)(SiHn-1R4-n)] (n = 1, 2) and nickel bis(silyl) complexes cis-[Ni(iPr2Im) 2(SiHn-1R4-n)2] (n = 1, 2, 3) were synthesized by stoichiometric reactions of 1 with hydrosilanes H nSiR4-n, and fully characterized by X-ray diffraction and spectroscopic methods. These hydrido silyl complexes are examples where the full oxidative addition step is hindered. They have, as a result of the remaining Si-H interactions, remarkably short Si-H distances and feature a unique dynamic behavior in solution. Cis-[Ni(iPr2Im)2(H)(SiMePh 2)] (cis-5) shows in solution at room temperature a dynamic site exchange of the NHC ligands, H-D exchange with C6D6 to give the deuteride complex cis-[Ni(iPr2Im)2(D)(SiMePh 2)] (cis-5-D), and at elevated temperatures an irreversible isomerization to trans-[Ni(iPr2Im)2(D)(SiMePh 2)] (trans-5-D). Reactions with sterically less demanding silanes give cis-configured bis(silyl) complexes accompanied by the release of dihydrogen. These complexes display, similarly to the hydrido silyl complexes, interestingly short Si-Si distances. Complex 1 reacts with 4 eq. HSi(OEt) 3, in contrast to all the other silanes used in this study, to give the trans-configured bis(silyl) complex trans-[Ni(iPr2Im) 2Ni(Si(OEt)3)2] (trans-12). The addition of two equivalents of Ph2SiH2 to 1 results, at elevated temperatures, in the formation of the dinuclear complex [{(iPr 2Im)Ni-μ2-(HSiPh2)}2] (6). This diamagnetic, formal Ni(i) complex exhibits a long Ni-Ni bond in the solid state, as established by X-ray diffraction. The capability of the electron rich {Ni(iPr2Im)2} complex fragment to activate Si-H bonds was applied catalytically in the deuteration of Et3Si-H to Et 3Si-D employing C6D6 as a convenient deuterium source. Furthermore, we show that 1 serves as a catalyst for the acceptorless dehydrogenative coupling of Ph2SiH2 to the corresponding disilane Ph2HSi-SiHPh2 and trisilane Ph 2HSi-Si(Ph)2-SiHPh2, and the coupling of PhSiH3 to give a mixture of cyclic and linear polysilanes with high polydispersity (Mw = 1119; Mn = 924; Mw/M n = 1.2). The capability of 1 to catalyze the formal reverse reaction as well is demonstrated by the hydrogenation of disilanes. The hydrogenation of the disilanes Ph2MeSi-SiMePh2 and PhMe 2Si-SiMe2Ph to the corresponding hydrosilanes Ph 2MeSi-H and PhMe2Si-H, respectively, proceeds effectively in the presence of 1 under very mild conditions (room temperature, 1.8 bar H2 pressure).
Synthesis of silylium and germylium ions by a substituent exchange reaction
Schaefer, Andre,Reissmann, Matti,Jung, Sebastian,Schaefer, Annemarie,Saak, Wolfgang,Brendler, Erica,Mueller, Thomas
, p. 4713 - 4722 (2013/09/24)
The reaction of diarylalkylsilanes and -germanes with trityl cation in the presence of a weakly coordinating anion to give the corresponding triarylsilylium or -germylium ions was investigated. This reaction provides a facile access to a larger range of these sterically highly hindered Lewis acids. The factors that promote the substituent exchange were studied, and significant effects of the substituent, of the solvent, and of the group 14 element were revealed. A combined solid-state XRD and NMR investigation of the tris(pentamethylphenyl) silylium borate [(Me5C6) 3Si]2[B12Cl12] disclosed the trigonal planar coordination environment of the silicon atom in this silylium ion. NMR investigations indicate for 2,4,6-triisopropylphenyl-substituted silylium and germylium ions the onset of C-H···E + three-center interactions (E = Si, Ge) between the distant CH bond of the isopropyl group and the positively charged group 14 element atom.
