- Trimethylsilylketene: Reactivity and Stabilization
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Me3SiCH=C=O is stable thermally, and is less reactive than t-BuCH=C=O toward H2O in neutral hydration, but in acid and base induced hydrations the reactivity is accelerated relative to alkylketenes.The contrasting reactivities are due to the relative degree of silicon stabilization of the ground state and the different transition states.
- Allen, Annette D.,Tidwell, Thomas T.
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- Electrochemical synthesis of 1,2-disilylethanes from α-silylacetic acids
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The synthesis of 1,2-disilylethanes [R1R2R 3Si(CH2)2SiR1R2R 3] is usually conducted by using noble metal reagents or catalysts. This work describes a new electrochemical synthetic method for their preparation in good yields by oxidation of α-silylacetic acids at Pt anodes (Kolbe electrolysis). Most of the reported synthesized 1,2-disilylethanes in this work are unknown.
- Shtelman, Alex V.,Becker, James Y.
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p. 4710 - 4714
(2011/07/08)
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- A convenient method for the synthesis of α-silylacetic acids
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A method is described for the preparation of α-silylacetic acids of the type R3SiCH2CO2H by treating trimethylsilyl acetate with LDA followed by quenching with chlorosilanes.
- Shtelman, Alex V.,Becker, James Y.
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p. 3101 - 3103
(2008/09/20)
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- Preparation and reactivity of persistent and stable silyl-substituted bisketenes
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2,3-Bis(trimethylsilyl)-1,3-butadiene-1,4-dione (1) is formed as the only product on thermolysis of 3,4-bis(trimethylsilyl)cyclobut-3-ene-1,2-dione (2), and the rate of ring opening of 2 is comparable to that of substituted cyclobutenes and cyclobutenones. Photolysis of 2 also forms 1, which reacts with ethanol in a stepwise fashion with faster addition of one ethanol molecule to give an isolable monoketene 18, which reacts in a further slower step to give succinate diesters, accompanied by desilylation. 2,3-Bis(tert-butyldimethylsilyl)-1,3-butadiene-1,4-dione (3), prepared analogously to 1, similarly adds one molecule of methanol to give the isolable monoketene 20, which then reacts to give dimethyl 2,3-bis(tert-butyldimethylsilyl)succinate (21) as the major product. The reaction of 1 with H2O is faster than with alcohols and forms (E)- and (Z)-2,3-bis(trimethylsilyl)succinic anhydrides (13) as the first observed products. The reactivity of 1 with different nucleophilic solvents is correlated by the Winstein-Grunwald equation and increases with both solvent ionizing power and solvent nucleophilicity.
- Zhao, Da-Chuan,Allen, Annette D.,Tidwell, Thomas T.
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p. 10097 - 10103
(2007/10/02)
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- Ultrasound-induced Synthesis of Trimethylsilylacetic Acid Trimethylsilylester
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The reaction of bromoacetic acid trimethylsilylester with zinc in presence of chlorotrimethylsilane is promoted by sono-waves.The trimethylsilylacetic acid trimethylsilylester could be obtained in high yield.Different products are observed in presence of dichlorodimethylsilane.Mechanistical aspects are discussed.
- Nietzschmann, Eckhart,Boege, Olaf,Tzschach, Alfred
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p. 281 - 284
(2007/10/02)
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- A SIMPLE PREPARATION OF TRIMETHYLSILYL ACETIC ACID
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A facile access to trimethylsilyl acetic acid is described.The method involves the preparation of the corresponding trimethylsilyl ester in fairly qood yield (70 percent).
- Bellassoued, M.,Dubois, J.E.,Bertounesque, E.
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p. 1181 - 1184
(2007/10/02)
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- Synthesis of Vinylcyclopropanes, Cyclopropyl Vinyl Ketones, and 3-Pyrazolyl Vinyl Ketones from 1-Diazo-3-trimethylsilylpropanone
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Reaction of 1-diazo-3-trimethylsilylpropanone with olefins in the presence of cupric acetylacetonate (Cu(acac)2) affords cyclopropyl trimethylsilylmethyl ketones.One-flask procedure for the formation of these silylated ketones and subsequent treatment with organometallics or with lithium diisopropylamide (LDA) and then carbonyl compounds gives a variety of vinylcyclopropanes or cyclopropyl vinyl ketones in good yields, respectively.Cycloaddition of 1-diazo-3-trimethylsilylpropanone with acetylenes and similar carbon-carbon bond formation at the side chain of the cycloadducts lead to 3-pyrazolyl vinyl ketones.
- Tsuge, Otohiko,Kanemasa, Shuji,Suzuki, Toshiro,Matsuda, Koyo
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p. 2851 - 2860
(2007/10/02)
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- Reactions of Trialkylsilyl Trifluoromethanesulfonates, II. - Synthesis of O-Alkyl-O-(trialkylsilyl)ketene Acetals and 2-(Trialkylsilyl)carboxylates
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Alkyl carboxylates 2 are silylated by trialkylsilyl triflates 1 in the presence of triethylamine (3) to yield ketene acetals 4.In reactions of the esters 6 mixtures of ketene acetals 7 and at the α-carbon silylated esters 8 are obtained.Ethanoic acid esters and lactones are doubly silylated to give the products 11, 12, and 15, respectively.Under suitable conditions silylation of the esters 10 gives rise to the 2-trimethylsilylethanoic acid esters 13.The thermodynamically more stable products are obtained.Product distributions depend on the structure of the esters and the silylating agents 1.
- Emde, Herbert,Simchen, Gerhard
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p. 816 - 834
(2007/10/02)
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