- Markovnikov Hydrosilylation of Alkynes with Tertiary Silanes Catalyzed by Dinuclear Cobalt Carbonyl Complexes with NHC Ligation
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Metal-catalyzed hydrosilylation of alkynes is an ideal atom-economic method to prepare vinylsilanes that are useful reagents in the organic synthesis and silicone industry. Although great success has been made in the preparation of β-vinylsilanes by metal-catalyzed hydrosilylation reactions of alkynes, reported metal-catalyzed reactions for the synthesis of α-vinylsilanes suffer from narrow substrate scope and/or poor selectivity. Herein, we present selective Markovnikov hydrosilylation reactions of terminal alkynes with tertiary silanes using a dicobalt carbonyl N-heterocyclic carbene (NHC) complex [(IPr)2Co2(CO)6] (IPr = 1,3-di(2,6-diisopropylphenyl)imidazol-2-ylidene) as catalyst. This cobalt catalyst effects the hydrosilylation of both alkyl- and aryl-substituted terminal alkynes with a variety of tertiary silanes with good functional group compatibility, furnishing α-vinylsilanes with high yields and high α/β selectivity. Mechanistic study revealed that the stoichiometric reactions of [(IPr)2Co2(CO)6] with PhCCH and HSiEt3 can furnish the dinuclear cobalt alkyne and mononuclear cobalt silyl complexes [(IPr)(CO)2Co(μ-ν2:ν2-HCCPh)Co(CO)3], [(IPr)(CO)2Co(μ- ν2:ν2-HCCPh)Co(CO)2(IPr)], and [(IPr)Co(CO)3(SiEt3)], respectively. Both dicobalt bridging alkyne complexes can react with HSiEt3 to yield α-triethylsilyl styrene and effect the catalytic Markovnikov hydrosilylation reaction. However, the mono(NHC) dicobalt complex [(IPr)(CO)2Co(μ- ν2:ν2-HCCPh)Co(CO)3] exhibits higher catalytic activity over the di(NHC)-dicobalt complexes. The cobalt silyl complex [(IPr)Co(CO)3(SiEt3)] is ineffective in catalyzing the hydrosilylation reaction. Deuterium labeling experiments with PhCCD and DSiEt3 indicates the syn-addition nature of the hydrosilylation reaction. The absence of deuterium scrambling in the hydrosilylation products formed from the catalytic reaction of PhCCH with a mixture of DSiEt3 and HSi(OEt)3 hints that mononuclear cobalt species are less likely the in-cycle species. These observations, in addition to the evident of nonsymmetric Co2C2-butterfly core in the structure of [(IPr)(CO)2Co(μ- ν2:ν2-HCCPh)Co(CO)3], point out that mono(IPr)-dicobalt species are the genuine catalysts for the cobalt-catalyzed hydrosilylation reaction and that the high α selectivity of the catalytic system originates from the joint play of the dicobalt carbonyl species to coordinate alkynes in the Co(μ- ν2:ν2-HCCR′)Co mode and the steric demanding nature of IPr ligand.
- Deng, Liang,Lai, Yuhang,Leng, Xuebing,Wang, Dongyang,Wang, Peng,Xiao, Jie
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supporting information
p. 12847 - 12856
(2021/08/24)
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- Dichloro(ethylenediamine)platinum(II), a water-soluble analog of the antitumor cisplatin, as a heterogeneous catalyst for a stereoselective hydrosilylation of alkynes under neat conditions
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A stereoselective method for the hydrosilylation of internal and terminal alkynes under heterogeneous catalysis by dichloro(ethylenediamine)platinum(II) is discussed. This commercially available platinum complex operates under neat conditions at 90 °C, pr
- Fotie, Jean,Enechojo Agbo, Mercy,Qu, Fengrui,Tolar, Trevor
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supporting information
(2020/08/13)
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- Hydrosilylation of alkynes catalysed by platinum on titania
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The heterogeneous hydrosilylation of alkynes catalysed by platinum on titania is reported. A variety of hydrosilanes react with both terminal and internal alkynes to furnish the corresponding vinyl silanes in high yields and short reaction times as well as in a regio- and stereoselective manner. The catalyst can be easily recovered and reused in several consecutive cycles.
- Alonso, Francisco,Buitrago, Robison,Moglie, Yanina,Ruiz-Martínez, Javier,Sepúlveda-Escribano, Antonio,Yus, Miguel
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experimental part
p. 368 - 372
(2011/02/16)
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- Platinum(ii) complexes with polydentate N-heterocyclic carbenes: Synthesis, structural characterization and hydrosilylation catalysis
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The platinum(ii) complexes of multidentate N-heterocyclic carbenes, [Pt(L1)2Cl](PF6) (1, L1 = N-methyl-N-(2-pyrimidinyl) imidazolylidene), [Pt(L2)Cl](PF6) (2, L2 = N-butyl-N-(1,10- phenanthrolin-2-yl)imidazolylidene), [PtL
- Lu, Chunxin,Gu, Shaojin,Chen, Wanzhi,Qiu, Huayu
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experimental part
p. 4198 - 4204
(2010/07/09)
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- Tri(t-butyl)phosphine-assisted selective hydrosilylation of terminal alkynes
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A highly efficient and regio-/stereoselective method of hydrosilylating terminal alkynes was developed using Pt(DVDS)-tri(t-butyl)phosphine catalyst system at room temperature. Trans-products or alpha-products were obtained almost exclusively depending on
- Wu, Wei,Zhang, Xiao Yun,Kang, Shou Xing,Gao, Yan Min
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experimental part
p. 312 - 316
(2010/11/20)
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- Gold-film-catalysed hydrosilylation of alkynes by microwave-assisted, continuous-flow organic synthesis (MACOS)
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Thin gold films on the surface of glass capillaries have proven to be highly active catalysts for the rapid hydrosilylation of alkynes that are flowed through the reactor while being heated by microwave irradiation. The films are able to be reused at least five times with no loss of activity and with no detectable levels of gold showing up in the hydrosilylated products.
- Shore, Gjergji,Organ, Michael G.
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experimental part
p. 9641 - 9646
(2009/09/30)
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- Olefin ring closing metathesis and hydrosilylation reaction in aqueous medium by grubbs second generation ruthenium catalyst
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(Chemical Equation Presented) The Grubbs second generation ruthenium catalyst was shown to catalyze various olefin ring closing metathesis and hydrosilylation reactions in aqueous medium. Reactions proceeded in pure water without any additives or cosolvents, in a short period of time. We found that inhomogeneity of the reaction mixture does not prevent high conversion (70-95%) of the products in both reactions.
- Polshettiwar, Vivek,Varma, Rajender S.
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supporting information; experimental part
p. 7417 - 7419
(2009/05/07)
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- The activity of Pt/SiO2 catalysts obtained by the sol-gel method in the hydrosilylation of 1-alkynes
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Heterogeneous platinum catalysts (Pt/SiO2) obtained by the sol-gel process at pH 3 and 9 have been used in the hydrosilylation reaction of 1-alkynes using various silanes. Once the catalysts were activated they were used in the hydrosilylation
- Jimenez, Rafael,Martinez-Rosales, J. Merced,Cervantes, Jorge
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p. 1370 - 1375
(2007/10/03)
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- Efficient Pd(O)-catalyzed hydrosilylation of alkynes with triorganosilanes
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An electron-rich Pd(0) complex, a Pd2(dba)3·CHCl3- tricyclohexylphosphine combination catalyzes highly efficient hydrosilylation of alkynes at room temperature with Ph3SiH or Ph2MeSiH without solvents
- Motoda, Dai,Shinokubo, Hiroshi,Oshima, Koichiro
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p. 1529 - 1531
(2007/10/03)
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- Metal supported catalysts obtained by sol-gel in the hydrosilylation of phenylacetylene with R3SiH organosilanes (R3 = Ph3, Ph2Me, and PhMe2)
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The hydrosilylation reaction of phenylacetylene, generated on the surface of solid catalysts (such as Pt and Ru) supported on inorganic matrices such as MgO obtained by the sol-gel process, yields vinylsilanes as the main products. The products' distribut
- Jimenez, Rafael,Lopez, Juan Manuel,Cervantes, Jorge
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p. 1491 - 1495
(2007/10/03)
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- Chemistry of silyl thioketones. Part 8. Photo-induced cycloadditions of silyl thioketones with olefins
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Photo-induced cycloadditions of phenyl triphenylsilyl thioketone 1 with electron-poor olefins (acrylonitrile, methyl acrylate and cis- and trans-1,2-dichloroethene) gave silyl thietanes in a regio- and highly stereo-selective manner.In contrast, reaction with vinyl ethers gave thietanes without any regio- or stereo-control.Reaction with α-methylstyrene and 2,3-dimethylbut-2-ene gave open chain products.Desilylation of silyl thietanes occurs with prevalent inversion of configuration at the carbon bearing the silicon group.
- Bonini, Bianca Flavia,Franchini, Mauro Comes,Fochi, Mariafrancesca,Mazzanti, Germana,Ricci, Alfredo,et al.
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p. 2039 - 2044
(2007/10/02)
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- Steuerung der Nickel(0)-katalysierten Hydrosilylierung von Phenylacetylen mit Phosphorliganden
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We report here the first systematic investigation of the effects of concentration and properties of tertiary phosphines on the chemoselectivity of the homogeneous catalytic hydrosilylation of phenylacetylene with triphenylsilane using Nickel(0) catalyst.T
- Bartik, Tamas,Nagy, Gabor,Kvintovics, Pal,Happ, Berit
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- Organosilicon compounds with functional groups proximate to silicon. XVII. Synthetic and mechanistic aspects of the lithiation of α,β-epoxyalkylsilanes and related α-heterosubstituted epoxides
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A series of α-heterosubstituted epoxides, , has been found to undergo lithiation in the temperature range of -75 to -115 deg C at the C-H bond of the epoxide.The substituent Z could be Me3Si, Ph3Si, n-Bu3Sn, Ph3Sn, PhSO2, (OEt)2PO and Ph; the groups R and R' were H, Ph and n-C6H13; and the lithiating reagents were n-butyllithium, t-butyllithium and lithium diisopropylamide in donor media of THF or TMEDA.The lithiation occurs with retention of configuration and the resulting lithio-epoxide is unstable above 0 deg C, decomposing in a carbenoid manner.The lithiation is facile except for compounds where Z and R (an alkyl or aryl) are cis-oriented; where Z = R3Sn, lithiation occurs by tin-lithium, rather than hydrogen-lithium, exchange.The lithio-epoxides thereby generated can be quenched with various reagents to yield epoxides where the epoxide H has been replaced by D, Me3Sn, R, RCO and COOH.The utility of this procedure in organic synthesis is emphasized.Finally, the possible explanations for the acidity of such α-heterosubstituted epoxides and for the relative stability of the derived lithio-epoxides are considered and assessed.
- Eisch, John J.,Galle, James E.
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p. 293 - 314
(2007/10/02)
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- Palladium-Catalyzed Regio- and Stereoselective Aryldesilylation of α-Silylstyrenes with Arenediazonium Salts
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α-Trialkylsilylstyrenes easily reacted with arenediazonium tetrafluoroborates+ BF4- (4)> to give (E)-PhCH=CHAr under palladium(0) catalysis.The bulky substituents on silicon gave better stereoselectivity.
- Ikenaga, Kazutoshi,Matsumoto, Satoshi,Kikukawa, Kiyoshi,Matsuda, Tsutomu
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p. 873 - 876
(2007/10/02)
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- 1H, 13C and 29Si NMR study of α- and β-silylstyrenes and their adducts with dichlorocarbene
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1H, 13C and 29NMR spectra for the α- and β-silylstyrenes (E)-PhCH=CHSiR3 (I) and PhC(SiR3)=CH2 (II) (R = Cl, Me, Ph), and those for some dichlorocarbene adducts of I and II (R = Me, Ph), were examined.From the 13C NMR data, the phenyl substituent in the m
- E. Liepins,Goldberg, Yu.,Iovel, I.,Lukevics, E.
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p. 301 - 312
(2007/10/02)
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- HYDROSILYLATION OF THE CC TRIPLE BOND BY PHENYL- AND THIENYL-SILANES
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The effects of the structures of the hydrosilane and the acetylene derivative, catalyst, temperature and solvent on the yields and ratio of isomers during the hydrosilylation of phenylacetylene, 2-(ethynyl)thiophene, methyl propiolate, propargyl alcohol a
- Lukevics, E.,Sturkovich, R. Ya.,Pudova, O. A.
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p. 151 - 158
(2007/10/02)
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