- Basic Copper Carbonate-Catalyzed Silyl Conjugate Additions to α,β-Unsaturated Carbonyls in Water
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We report here the silylation of α,β-unsaturated acceptors in water at room temperature using a copper catalyst. A broad substrate scope, including chalcone derivatives, esters, nitrile, and dienones, has been explored. In all cases, the reaction proceede
- Wang, Wei,Li, Bo-Jie,Xiao, Zu-Feng,Yan, Feng,Wei, Peng-Ren,Wang, Lian-Sheng,Zhu, Lei
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- Conjugate addition of dimethylphenylsilyllithium to α,β-unsaturated carbonyl compounds mediated by sub-stoichiometric quantities of dimethylzinc
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Dimethylphenylsilyllithium undergoes conjugate addition to a variety of α,β-unsaturated enones in the presence of sub-stoichiometric amounts of dimethylzinc. Down to 10 mol % of Me2Zn facilitates these reactions to afford good to excellent yields of β-silylated products. This catalytic behavior is displayed when the Me2Zn used is generated in situ, from the addition of methyllithium to zinc (II) iodide or when used directly from a commercial source. This methodology in which sub-stoichiometric quantities of the reactive organometallic reagent are present at a given time may provide a route for catalytic enantioselective conjugate addition of trialkylsilyl moieties to enones.
- MacLean, Bonnie L.,Hennigar, Kimberlea A.,Kells, Kevin W.,Singer, Robert D.
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- Conjugate Addition of Zinc Halide Derived Trialkylsilyl(dialkyl)zincate Reagents to α,β-Unsaturated Carbonyl Compounds
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Trialkylsilyl(dialkyl)zincate reagents, PhMe2SiZnR2Li, (R = Alkyl), are easily prepared in THF solutions via the addition of two equivalents of methyllithium and one equivalent of dimethylphenylsilyllithium to zinc halides (ZnI2 or ZnCl2).The resulting zi
- Vaughan, Andrew,Singer, Robert D.
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- Method for preparing organic silicon compound by catalyzing chitosan-loaded copper film material
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The invention discloses a method for preparing an organosilicon compound by catalyzing a chitosan-loaded copper film material, which comprises the following steps: adding water into the chitosan-loaded copper film material, and uniformly stirring at room
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Paragraph 0037-0046
(2020/12/10)
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- Method used for preparing organic silicon compounds and beta-hydroxyl compounds via bivalent copper ion catalysis
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The invention relates to a method used for preparing organic silicon compounds and beta-hydroxyl compounds via bivalent copper ion catalysis. According to the method, a bivalent copper salt is taken as a catalyst, a pyridyl compound is taken as a ligand, bis(pinacolato)diboron dimethylsilane reagent is taken as a silicon reagent, and pure water is taken as a solvent; silicone additive reaction of alpha, beta-unsaturated carbonyl compounds with different substituent groups is carried out so as to obtain the organic silicon compounds; potassium bromide and peracetic acid are added directly without separation and purification of the organic silicon compounds, and the beta-hydroxyl compounds are obtained via oxidation. The advantages of the method are that: the method is simple and convenient; the raw materials are widely available; cost is relatively low; popularization is convenient; catalyst using amount is low; reaction yield is high; reaction conditions are mild; pure water is taken as the solvent; reaction is carried out at room temperature; operation is simple and convenient; application range is wide; the method is suitable for silicone additive reaction of alpha, beta- unsaturated carbonyl compounds of different types; one-pot method is adopted; and production efficiency is high.
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Paragraph 0114; 0115; 0116; 0117; 0118; 0119; 0120-0122
(2017/10/07)
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- In search of open-chain 1,3-stereocontrol
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Methylation of methyl 4-phenylpentanoate 25 gives the diastereoisomers methyl (2RS,4SR)-2-methyl-4-phenylpentanoate 26 and methyl (2RS,4RS)- 2-methyl-4-phenylpentanoate 27 in a ratio of 44:56. The aldehydes 3-dimethyl(phenyl)silylbutanal 28, 3-dimethyl(ph
- Barbero, Asun,Blakemore, David C.,Fleming, Ian,Wesley, Robert N.
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p. 1329 - 1352
(2007/10/03)
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- Conjugate Addition of the Phenyldimethylsilyl Group to αβ-Unsaturated Carbonyl Compounds Using a Silylzincate in Place of the Silylcuprate
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Lithium phenyldimethylsilyl(dialkyl)zincates add to a number of αβ-unsaturated carbonyl compounds to give, in most cases, higher yields of the conjugate addition product than we had achieved with the corresponding silylcuprate.
- Crump, Roger A. N. C.,Fleming, Ian,Urch, Christopher J.
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p. 701 - 706
(2007/10/02)
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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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- Direct Michael-Type Addition of Si-Groups to α,β-unsaturated β-Aryl-Substituted Enones with R3SiCl/Bu2Cu(CN)Li2
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(E)-5-Benzylidene-2-tert-butyl-6-methyl-1,3-dioxan-4-one (1) undergoes conjugative silylation (Me3Si, Et3Si, tBuMe2Si, Me2PhSi, products 2-5) with the reagent specified in the title.The reaction is highly diastereoselective, with formal anti addition of R
- Amberg, Willi,Seebach, Dieter
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p. 2439 - 2444
(2007/10/02)
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- PALLADIUM-CATALYZED 1,4-DISILYLATION OF α,β UNSATURATED KETONES WITH 1,1-DICHLORO-1-PHENYL-2,2,2-TRIMETHYLDISILANE
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1,4-Disilylation of α,β-unsaturated ketones proceeded with 1,1-dichloro-1-phenyl-2,2,2-trimethyldisilane in the presence of a phosphine-palladium catalyst in benzene.Treatment of the disilylation products with an excess of methyllithium generated β-silyl lithium enolates, of which hydrolysis and alkylation gave β-(phenyldimethylsilyl) ketones and anti β-silyl α-alkyl ketones, respectively.
- Hayashi, Tamio,Matsumoto, Yonetatsu,Ito, Yoshihiko
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p. 4147 - 4150
(2007/10/02)
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- 1,4-Addition of Triorganozincates and Silyldiorganozincates to α,β-Unsaturated Ketones
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Lithium and magnesium triorganozincates, prepared by combination of ZnCl2(TMEDA) with 3 molar equivalents of RLi or RMgX, or from dialkylzinc and 1 molar equivalent of RLi or RMgX, react with 2-cyclohexen-1-one (1) under mild conditions to produce moderate to good yields of the 1,4-addition products 2.The approximate reactivity order obtained from the product distribution using unsymmetrical zincates is tBuCH2 tBu, Me Me2PhSi.The latter groups are transferred with good selectivity from mixed reagents derived from Me2Zn.This sequence differs strikingly from that exhibited by unsymmetrical cuprates which transfer neopentyl very easily, and also tert-butyl more easily than the corresponding zincates.The methylation with Me3ZnLi is catalyzed by cobalt complexes.Other enones (7-13) generally give poor yields, and the cobalt-catalyzed methylation of isophorone (3) is complicated by a Kharasch-type deconjugation.Mixed silyldialkylzincates, Me2PhSiZnR2Li, produce the β-silyl ketones from a variety of unhindered or moderately hindered enones in practically useful yields; one example of an α,β-unsaturated ester (12) is also included.
- Tueckmantel, Werner,Oshima, Koichiro,Nozaki, Hitosi
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p. 1581 - 1593
(2007/10/02)
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