- Selective Electrochemical Hydrolysis of Hydrosilanes to Silanols via Anodically Generated Silyl Cations
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The first electrochemical hydrolysis of hydrosilanes to silanols under mild and neutral reaction conditions is reported. The practical protocol employs commercially available and cheap NHPI as a hydrogen-atom transfer (HAT) mediator and operates at room temperature with high selectivity, leading to various valuable silanols in moderate to good yields. Notably, this electrochemical method exhibits a broad substrate scope and high functional-group compatibility, and it is applicable to late-stage functionalization of complex molecules. Preliminary mechanistic studies suggest that the reaction appears to proceed through a nucleophilic substitution reaction of an electrogenerated silyl cation with H2O.
- Liang, Hao,Wang, Lu-Jun,Ji, Yun-Xing,Wang, Han,Zhang, Bo
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supporting information
p. 1839 - 1844
(2020/12/01)
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- Metal-free hydrogen evolution cross-coupling enabled by synergistic photoredox and polarity reversal catalysis
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A synergistic combination of photoredox and polarity reversal catalysis enabled a hydrogen evolution cross-coupling of silanes with H2O, alcohols, phenols, and silanols, which afforded the corresponding silanols, monosilyl ethers, and disilyl ethers, respectively, in moderate to excellent yields. The dehydrogenative cross-coupling of Si-H and O-H proceeded smoothly with broad substrate scope and good functional group compatibility in the presence of only an organophotocatalyst 4-CzIPN and a thiol HAT catalyst, without the requirement of any metals, external oxidants and proton reductants, which is distinct from the previously reported photocatalytic hydrogen evolution cross-coupling reactions where a proton reduction cocatalyst such as a cobalt complex is generally required. Mechanistically, a silyl cation intermediate is generated to facilitate the cross-coupling reaction, which therefore represents an unprecedented approach for the generation of silyl cationviavisible-light photoredox catalysis.
- Cao, Jilei,Lu, Kanghui,Ma, Lishuang,Yang, Xiaona,Zhou, Rong
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supporting information
p. 8988 - 8994
(2021/11/23)
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- Photocatalyzed cross-dehydrogenative coupling of silanes with alcohols and water
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An efficient method for the dehydrogenative coupling of silanes with alcohols under photocatalysis was developed. The reaction proceeded in the presence of Ru(bpy)3Cl2(0.5 mol%) under visible light irradiation in acetonitrile at room temperature. The developed methodology was also applicable for the synthesis of silanols using water as a coupling partner.
- Lv, Haiping,Laishram, Ronibala Devi,Chen, Jingchao,Khan, Ruhima,Zhu, Yuanbin,Wu, Shiyuan,Zhang, Jianqiang,Liu, Xingyuan,Fan, Baomin
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supporting information
p. 3660 - 3663
(2021/04/16)
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- Catalytic Enantioselective Dehydrogenative Si-O Coupling to Access Chiroptical Silicon-Stereogenic Siloxanes and Alkoxysilanes
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A rhodium-catalyzed enantioselective construction of triorgano-substituted silicon-stereogenic siloxanes and alkoxysilanes is developed. This process undergoes a direct intermolecular dehydrogenative Si-O coupling between dihydrosilanes with silanols or alocohols, giving access to a variety of highly functionalized chiral siloxanes and alkoxysilanes in decent yields with excellent stereocontrol, that significantly expand the chemical space of the silicon-centered chiral molecules. Further utility of this process was illustrated by the construction of CPL-active (circularly polarized luminescence) silicon-stereogenic alkoxysilane small organic molecules. Optically pure bis-alkoxysilane containing two silicon-stereogenic centers and three pyrene groups displayed a remarkable glum value with a high fluorescence quantum efficiency (glum = 0.011, φF = 0.55), which could have great potential application prospects in chiral organic optoelectronic materials.
- Zhu, Jiefeng,Chen, Shuyou,He, Chuan
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supporting information
p. 5301 - 5307
(2021/05/04)
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- Silicon-center chiral silicon-oxygen compound and preparation method thereof
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The invention belongs to the field of chiral silicon synthesis, and discloses a silicon-center chiral silicon-oxygen compound. The compound has a structure represented by general formula I shown in the specification. In the formula I, X is Si(R)n or a formula also shown in the specification, R is selected from alkyl, cycloalkyl and aryl, R is selected from alkyl, substituted phenyl and aryl, R is selected from alkyl, phenyl and substituted phenyl, n is 3, the three R are the same or different, R is selected from hydrogen and (C1-C4) alkyl, m is selected from 0, 1, 2 and 3, and Y is selected from substituted phenyl, substituted pyrenyl, aryl, heteroaryl and cycloalkyl. The invention also discloses a preparation method of the compound. Various highly functionalized chiral siloxanes and silyl ethers are obtained with good chemical, regional and stereo control and high yield, the variety of silicon center chiral compounds is expanded, and the method has the advantages of high enantioselectivity, wide substrate application range, mild reaction conditions, atom economy and the like. In addition, the compound provided by the invention has a huge application prospect in chiral organic photoelectric materials.
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Paragraph 0106-0109; 0111-0113
(2021/07/24)
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- Selective Manganese-Catalyzed Oxidation of Hydrosilanes to Silanols under Neutral Reaction Conditions
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The first manganese-catalyzed oxidation of organosilanes to silanols with H2O2 under neutral reaction conditions has been accomplished. A variety of organosilanes with alkyl, aryl, alknyl, and heterocyclic substituents were tolerated, as well as sterically hindered organosilanes. The oxidation appears to proceed by a concerted process involving a manganese hydroperoxide species. Featuring mild reaction conditions, fast oxidation, and no waste byproducts, the protocol allows a low-cost, eco-benign synthesis of both silanols and silanediols.
- Wang, Kaikai,Zhou, Jimei,Jiang, Yuting,Zhang, Miaomiao,Wang, Chao,Xue, Dong,Tang, Weijun,Sun, Huamin,Xiao, Jianliang,Li, Chaoqun
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supporting information
p. 6380 - 6384
(2019/05/06)
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- Hydrogenation of silyl formates: sustainable production of silanol and methanol from hydrosilane and carbon dioxide
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A new process for simultaneously obtaining two chemical building blocks, methanol and silanol, was realized starting from silyl formates which can be derived from silane and carbon dioxide. Understanding the reaction mechanism enabled us to improve the reaction efficiency by the addition of a small amount of methanol.
- Koo, Jangwoo,Kim, Seung Hyo,Hong, Soon Hyeok
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p. 4995 - 4998
(2018/05/23)
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- Synthesis, characterization and catalytic oxidation of organosilanes with a novel multilayer polyoxomolybdate containing mixed-valence antimony
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Oxidation of organosilanes is one of the pivotal reactions in organic synthesis and the corresponding products of silanols are widely as raw materials in industrial processes. In this paper, a new type of polyoxomolybdate containing mixed-valence antimony, [SbVSbIII4Mo18O66]7? (1a), has been isolated as tetramethyl ammonium salt in aqueous solution. The compound was structurally characterized by FT-IR, XPRD, TG, XPS, ESI–MS etc. It is the first time that the containing mixed-valence antimony polyoxomolybdate was used as a heterogeneous catalyst to efficaciously catalyze the oxidation of organosilanes to silanols under mild reaction conditions. Furthermore, the catalyst was stable and maintained its catalytic activity after three reaction cycles.
- Wang, Yaping,Lu, Jingkun,Ma, Xinyi,Niu, Yanjun,Singh, Vikram,Ma, Pengtao,Zhang, Chao,Niu, Jingyang,Wang, Jingping
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p. 167 - 174
(2018/04/24)
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- Method for synthesizing silanol from silane through catalytic oxidation by bipyridine manganese catalyst
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The invention discloses a method for synthesizing silanol from silane through catalytic oxidation by a bipyridine manganese catalyst. The method employs a bipyridine manganese complex formed by coordination of a manganese salt and a dipyridine compound as a catalyst and clean environment-friendly hydrogen peroxide as an oxidizing agent for catalytic oxidation of silane into silanol. Compared with conventional methods, the method provided by the invention has the advantages that the catalyst is low in price; the preparation method is simple; raw materials are easily available; and the method is low in the usage amount of the catalyst, wide in the range of usable substrates, mild in reaction conditions, simple to operate, friendly to environment, short in reaction time, high in yield, good in selectivity, low in industrialization cost, etc.
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Paragraph 0014; 0015; 0016; 0017-0043; 0056; 0057; 0058
(2018/01/11)
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- A convergent total synthesis of the telomerase inhibitor (±)-γ-rubromycin
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The total synthesis of the human telomerase inhibitor γ-rubromycin in its racemic form was accomplished in 3.8 % overall yield. The key feature of this synthesis is an efficient acid-catalyzed spiroketalization for the construction of the spiroketal core. The required electronically well-balanced spiroketal precursor was obtained by the convergent assembly of a naphthyl-substituted aldehyde, an α-methoxyallyl-γ-silyl-substituted phosphonate as the central C3 building block, and a highly functionalized aryl Grignard reagent. Another key feature is the late-stage construction of the isocoumarin moiety and a simultaneous protodesilylation furnishing the known methyl aryl ether protected precursor of γ-rubromycin. 3 building blocks + 3 acids→natural product: After the assembly of the crucial precursor from three highly functionalized building blocks, the pivotal spiroketalization was achieved with trifluoromethanesulfonic acid, the isocoumarin formation with fluoroboric acid, and the O-demethylation with the Lewis acid boron tribromide. (±)-γ-Rubromycin was thus synthesized in 18 steps with an overall yield of 3.8 % from commercially available precursors.
- Wilsdorf, Michael,Reissig, Hans-Ulrich
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supporting information
p. 4332 - 4336
(2014/05/06)
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- Synthesis of phenols via fluoride-free oxidation of arylsilanes and arylmethoxysilanes
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Rapid, efficient methods have been developed to prepare phenols from the oxidation of arylhydrosilanes. The effects of arene substituents and fluoride promoters on this process show that while electron-deficient arenes can undergo direct oxidation from the hydrosilane, electron-rich aromatics benefit from silane activation via oxidation to the methoxysilane using homogeneous or heterogeneous transition metal catalysis. The combination of these two oxidations into a streamlined flow procedure involving minimal processing of reaction intermediates is also reported.
- Rayment, Elizabeth J.,Summerhill, Nick,Anderson, Edward A.
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experimental part
p. 7052 - 7060
(2012/10/07)
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- Diorganotelluride-catalyzed oxidation of silanes to silanols under atmospheric oxygen
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Diorganotellurides efficiently catalyze the aerobic oxidation of organosilanes under photosensitized conditions to afford the corresponding silanols in excellent yield.
- Okada, Yasunori,Oba, Makoto,Arai, Atsushi,Tanaka, Kazuhito,Nishiyama, Kozaburo,Ando, Wataru
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scheme or table
p. 383 - 385
(2010/04/28)
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- Highly selective oxidation of organosilanes to silanols with hydrogen peroxide catalyzed by a lacunary polyoxotungstate
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Silanol synthesis: Divacant lacunary polyoxotungstate (nBu4N+)4[g- SiW10O34(H2O)2] (I) is an efficient homogeneous catalyst for highly selective oxidation of organosilanes to silanols with 30/60% aqueous H2O2. Various kinds of silanes 1 containing aryl, alkyl, alkenyl, alkynyl and alkoxy groups are chemoselectively converted into the corresponding silanols 2 in high yields with only one equivalent of aqueous H2O2 with respect to the substrate.
- Ishimoto, Ryo,Kamata, Keigo,Mizuno, Noritaka
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supporting information; experimental part
p. 8900 - 8904
(2010/01/16)
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- Supported gold nanoparticle catalyst for the selective oxidation of silanes to silanols in water
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Hydroxyapatite-supported gold nanoparticles (AuHAP) can act as highly efficient and reusable catalysts for the oxidation of diverse silanes into silanols in water; this is the first catalytic methodology for the selective synthesis of aliphatic silanols using water under organic-solvent-free conditions.
- Mitsudome, Takato,Noujima, Akifumi,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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supporting information; experimental part
p. 5302 - 5304
(2010/01/31)
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- A novel method for preparing silanols from silylmethanols
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Various types of silylmethanols were converted into their corresponding silanols in good to excellent yield under mild oxidation conditions using TEMPO (2,2,6,6-tetramethyl-l-piperidinyloxyl). Copyright
- Takeda, Daisuke,Oyama, Ryo,Yamada, Shozo
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p. 532 - 533
(2011/04/22)
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- Cross-coupling reactions of aromatic and heteroaromatic silanolates with aromatic and heteroaromatic halides
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The alkali-metal salts (potassium and sodium) of a large number of aryl- and heteroarylsilanols undergo efficient cross-coupling with a wide range of aromatic bromides and chlorides under mild conditions to form polysubstituted biaryls. The critical feature for the success of these coupling reactions and their considerable scope is the use of bis(tri-tert-butylphosphine)palladium. Under the optimized conditions, electron-rich, electron-poor, and sterically hindered arylsilanolates afford cross-coupling products in good yields. Many functional groups are compatible with the coupling conditions such as esters, ketones, acetals, ethers, silyl ethers, and dimethylamino groups. Two particularly challenging substrates, (2-benzofuranyl)dimethylsilanolate and (2,6-dichlorophenyl)dimethylsilanolate prepared as their sodium salts showed excellent activity in the coupling reactions, in the former case also with aromatic chlorides. General methods for the efficient synthesis of a wide range of aromatic silanols are also described.
- Denmark, Scott E.,Smith, Russell C.,Chang, Wen-Tau T.,Muhuhi, Joseck M.
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scheme or table
p. 3104 - 3118
(2009/08/07)
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- Supported silver-nanoparticle-catalyzed highly efficient aqueous oxidation of phenylsilanes to silanols
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Bon Apatite! Hydroxyapatite-supported silver nanoparticles act as a highly efficient heterogeneous catalyst for the oxidation of diverse phenylsilanes into silanols in water (see picture; C orange, H red, O blue, R purple, Si green), while suppressing significant condensation to the disiloxanes. The solid silver catalyst is readily reusable without any loss of activity or selectivity. (Figure Presented)
- Mitsudome, Takato,Arita, Shusuke,Mori, Haruhiko,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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supporting information; experimental part
p. 7938 - 7940
(2009/04/18)
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- Highly Efficient Iridium-Catalyzed Oxidation of Organosilanes to Silanols
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Hydrolytic oxidation of organosilanes to the corresponding silanols can be performed highly efficiently with a catalyst system of [IrCl(C8H 12)]2 under essentially neutral and mild conditions, and various types of silanols are produced in good to excellent yields.
- Lee, Youngjun,Seomoon, Dong,Kim, Sundae,Han, Hoon,Chang, Sukbok,Lee, Phil Ho
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p. 1741 - 1743
(2007/10/03)
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- Palladium-Catalyzed Silylation of Aryl Bromides Leading to Functionalized Aryldimethylsilanols
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Equation presented. A mild and general palladium-catalyzed insertion of 1,2-diethoxy-1,1,2,2-tetramethyldisilane into a variety of aryl bromides affords the aryldimethylsilyl ethers in high yields. Hydrolysis of the ethers under pH-optimized conditions results in the exclusive formation of the desired aryldimethylsilanols.
- Denmark, Scott E.,Kallemeyn, Jeffrey M.
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p. 3483 - 3486
(2007/10/03)
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- Novel carbon-carbon bond formation through Mizoroki-Heck type reaction of silanols and organotin compounds
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The reaction of dimethyl(phenyl)silanol with butyl acrylate in the presence of a stoichiometric amount of Pd(OAc)2 or by a combined use of 0.1 molar amount of Pd(OAc)2 and Cu(OAc)2/LiOAc (molar ratio 3/2) gave butyl cinnamate in 76% or 57% yield, respectively. The similar reaction with tributyl(phenyl)tin also proceeded in 77% yield. The organotin compound was shown to react faster than the sitanol, although the tin reagent sometimes induced undesirable homocoupling, while the reaction with silanol did not give such by-product.
- Hirabayashi, Kazunori,Ando, Jun-Ichi,Kawashima, Jun,Nishihara, Yasushi,Mori, Atsunori,Hiyama, Tamejiro
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p. 1409 - 1417
(2007/10/03)
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- A new transformation of silanols. Palladium-catalyzed cross-coupling with organic halides in the presence of silver(I) oxide
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(equation presented) The reactions of aryl-and alkenylsilanols with organic halides are found to proceed in a catalyst system of 5 mol % of Pd(PPh3)4 and Ag2O (1 equiv) to give the corresponding coupling products in up to 84% yield. ? Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Yoshida, Kyoto 606-8501, Japan.
- Hirabayashi, Kazunori,Kawashima, Jun,Nishihara, Yasushi,Mori, Atsunori,Hiyama, Tamejiro
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p. 299 - 301
(2008/02/13)
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- UEBER DIE Si-N-BINDUNG. XLIII. KINETISCHE UNTERSUCHUNGEN ZUR HYDROLYSE VON SILYLURETHANEN DES TYPS (p-XC6H4)Me2SiN(Ph)COOEt
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Hydrolysis reactions of silylurethanes ( p-XC6H4)Me2SiN(Ph)COOEt with X = MeO, Me, H or Cl in aqueous buffer solutions, with pH values from 1.73 to 10.00 and at temperatures of 20, 30, and 40 deg C were studied.The catalytic rate constants for the acid- and base-catalysed reactions and for the "non-catalysed" reaction k(H3O+), k(CH3COO-), k(NH3), k(OH-), and k0 and the Broensted coefficients for the general base-catalysed reactions were evaluated from the pseudo first-order rate constants kexp, determined by UV spectroscopy.The ρ values of the reactions can be derived from the ? constants given by Jaffe.Activation parameters can be obtained by means of the Arrhenius or Eyring equation.From the catalytic constants, Broensted coefficients, ρ values and activation parameters we derive mechanisms for the acid-and general base-catalysed reactions.Conclusions about these mechanisms are compared with the results obtained with the silylurethanes Me3Si(p-XC6H4)NCOOEt.
- Haenig, K.,Grosse-Ruyken, H.,Ruehlmann, K.,Schlapa, J.
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p. 145 - 158
(2007/10/02)
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