- Metastable ion study of organosilicon compounds. Part IX. CH3COOSi(CH3)3 and CF3COOSi(CH3)3
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The unimolecular metastable dissociation of trimethylsilyl acetate, CH3COOSi(CH3)3 (1), and its fluorine analogue, trimethylsilyl trifluoroacetate, CF3COOSi(CH3)3 (2), upon electron impact have been investigated by means of a B/E linked scan, high resolution data, and D-labeling. The results are compared with those of the carbon analogue, tert-butyl acetate, CH3COOC(CH3)3 (3). No molecular ion of any of these compounds can be observed, but loss of CH3 occurs exclusively from the trimethylsilyl or tert-butyl groups. The fragmentation of 1+. is slightly different from that of 3+., and quite different from that of 2+.. In the case of 3+., (CH3)2C=O is eliminated from [3-CH3]+, giving rise to the peak at m/z 43, but the loss of (CH3)2Si=O does not occur from [1-CH3]+. In the case of 2+., an interesting fluorine atom (F) migration is observed.
- Mori, Shigeru,Okada, Fumio,Sekiguchi, Osamu,Fujishige, Masao,Koitabashi, Risei,Tajima, Susumu
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- Chemoselective Cleavage of Si-C(sp3) Bonds in Unactivated Tetraalkylsilanes Using Iodine Tris(trifluoroacetate)
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Organosilanes are synthetically useful reagents and precursors in organic chemistry. However, the typical inertness of unactivated Si-C(sp3) bonds under conventional reaction conditions has hampered the application of simple tetraalkylsilanes in organic synthesis. Herein we report the chemoselective cleavage of Si-C(sp3) bonds of unactivated tetraalkylsilanes using iodine tris(trifluoroacetate). The reaction proceeds smoothly under mild conditions (-50 °C to room temperature) and tolerates various polar functional groups, thus enabling subsequent Tamao-Fleming oxidation to provide the corresponding alcohols. NMR experiments and density functional theory calculations on the reaction indicate that the transfer of alkyl groups from Si to the I(III) center and the formation of the Si-O bond proceed concertedly to afford an alkyl-λ3-iodane and silyl trifluoroacetate. The developed method enables the use of unactivated tetraalkylsilanes as highly stable synthetic precursors.
- Matsuoka, Keitaro,Komami, Narumi,Kojima, Masahiro,Mita, Tsuyoshi,Suzuki, Kimichi,Maeda, Satoshi,Yoshino, Tatsuhiko,Matsunaga, Shigeki
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supporting information
p. 103 - 108
(2021/01/13)
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- TREATING AGENT COMPOSITION FOR BEVEL PART AND METHOD FOR MANUFACTURING WAFER
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This beveled part treatment agent composition is used to treat a beveled part of a wafer and contains a silylating agent, wherein the bevel part treatment agent composition has characteristics in which a surface modification index Y and a surface modification index Z measured by prescribed procedures satisfies 0.5 ≤ Y / Z ≤ 1.0.
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Paragraph 0069
(2021/01/20)
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- Method for Producing Acyloxysilanes, Acyloxysilanes Obtained Thereby, and Use of Same
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An object of the invention is to provide a method for efficiently producing an acyloxysilane which is useful as a functional chemical, an acyloxysilane obtained thereby, and the use thereof. The present invention provides: a method for producing an acyloxysilane, including a reaction step of reacting an alkoxysilane with a carboxylic anhydride in the presence of a catalyst, wherein the alkoxysilane is a specified alkoxysilane represented by General Formula (I), the carboxylic anhydride is a specified carboxylic acid represented by General Formula (IIA) or (IIB), the catalyst is an acid catalyst, and an acyloxysilane obtained in the reaction step is a specified acyloxysilane represented by General Formula (IIIA) or (IIIB); and the use of the acyloxysilane as a surface treatment agent or the like.
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Paragraph 0131
(2018/03/25)
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- Reaction of 10,10-dimethyl-9-trimethylsiloxy-9,10-dihydrophenanthrene-9- carbonitrile with acids
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The behavior of 10,10-dimethyl-9-trimethylsiloxy-9,10-dihydrophenanthrene- 9-carbonitrile in trifluoromethanesulfonic acid and acid systems CF 3SO3H-CD2Cl2, HSO 3F-SO2ClF-CD2Cl2, and CF 3COOH-CD2Cl2 were studied by NMR spectroscopy. Principal reaction schemes were determined; the first step in these schemes is protonation of the initial compound at the oxygen or nitrogen atom.
- Bushmelev,Genaev,Sal'nikov,Shubin
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experimental part
p. 1057 - 1061
(2011/11/12)
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- Chloride-free method to synthesise new ionic liquids with mixed borate anions
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A new chloride-free method to synthesize ionic liquids (ILs) with mixed borate anions was demonstrated. The anions used for the study were derived from [BF4]- by replacement of F- by mono- or bidentate ligands. The proposed method was depended on the type of ligand, while moisture exclusion and dried starting materials and solvent were used to minimize water content. The starting materials were heated to reflux in acetonitrile (MeCN) as solvent for monodentate ligands. The [BF 4]- compounds were diluted in MeCN to prevent the formation of bridged anions and the trime-thylsilyl compounds were added at a temperature of 45 °C. The proposed method opened new opportunities for preparing new ILs for different applications including their use as electrolytes in electrochemical double layer capacitors and lithium ion batteries.
- Schreiner, Christian,Amereller, Marius,Gores, Heiner J.
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experimental part
p. 2270 - 2272
(2009/10/23)
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- Tetrafluorine-containing ketones and acetoacetates: Synthesis and mechanistic study
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Addition of trimethylsilyl trifluoroacetate to the carbanions of α-fluorobenzyl-phosphonate (3) or diisopropyl(fluorocarbethoxymethyl) phosphonate (9) formed the corresponding intermediates [CF3C(O)CFPh] -Li+ (10) and [CF3C(O)CFCO2Et] -Li+ (11), respectively. Subsequent protonation, alkylation or allylation of 10 and 11 afforded trifluoromethyl fluorobenzyl ketones 12 and ethyl 2,4,4,4-tetra-fluoroacetoacetates 13. Based on the results obtained, a plausible mechanism was proposed.
- Tsai, Hou-Jen,Hsieh, Chi-Wei
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p. 749 - 757
(2008/03/11)
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- B(C6F5)3-catalyzed allylation of propargyl acetates with allylsilanes.
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[reaction: see text] An efficient method for the B(C(6)F(5))(3)-catalyzed allylation of secondary propargylic alcohol derivatives with allylsilanes has been developed. This method allows for the facile synthesis of a variety of 1,5-enynes in good to high yields with a number of functionalities, such as nitro, chloro, ester, and boronic ester, being tolerated under the reaction conditions.
- Schwier, Todd,Rubin, Michael,Gevorgyan, Vladimir
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p. 1999 - 2001
(2007/10/03)
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- Application of fluorocarbethoxy-substituted phosphonate: A facile entry to substituted 2-fluoro-3-oxoesters
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Diethyl(fluorocarbethoxymethyl)phosphonate 1a or diisopropyl(fluorocarbethoxymethyl)phosphonate 1b, prepared from triethyl phosphite or triisopropyl phosphite with ethyl bromofluoroacetate, react with n-butyllithium in THF to give the corresponding phosphonate carbanions [(RO)2P(O)CFCO2Et]-Li+ 2a (R = Et) and 2b (R = i-Pr). Addition of trimethylsilyltrifluoroacetate CF3C(O)OSiMe3 to a THF solution of phosphonate carbanions formed the enolate of ethyl trifluoroacetylfluoroacetate [CF3C(O)CFCO2Et]-Li+ 3. Subsequent protonation, alkylation or allylation of the enolate afforded substituted 2,4,4,4-tetrafluoro-3-oxoesters CF3C(O)CFR1CO2Et 10.
- Tsai, Hou-Jen
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- Reactions of Trialkylsilyl Trifluoromethanesulfonates, X. - N-(Trifluoroacetyl)-α,β-didehydro-α-amino Carboxylic Acid Esters from 2--3-(trimethylsiloxy)carboxylic Acid Esters by Elimination of Trimethylsilanol
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α-Amino-β-(trimethylsiloxy)carboxylates 4 are obtained by trimethylsiloxy alkylation of the ketene acetal 1 with aldehydes 2 in the presence of trimethylsilyl triflate (3). β-Elimination of trimethylsilanol from the esters 4 by means of trifluoroacetic acid anhydride (8) or methanesulfonic acid anhydride (15) yields (Z)-didehydro amino acid esters 7.The course of the elimination reaction is studied.
- Seethaler, Toni,Simchen, Gerhard
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- Thermolysis of trimethylsilyl esters: an ultraviolet photoelectron spectroscopy study
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The thermolytic behaviour of trimethylsilyl trifluoromethanesulfonate, 1, trimethylsilyl trifluoroacetate, 2, and trimethylsilyl acetate, 3, has been investigated by ultraviolet photoelectron spectroscopy.Acetate 3 undergoes decomposition only to a small extent at 800 deg C via the mechanism shown in Scheme 1 (X = Si); only acetic acid and starting material are detected.In contrast with this result, 1 and 2 decompose completely at 725-800 deg C and yield products which cannot be derived via the mechanism shown in Scheme 1.Evidence is presented to support our proposal that the thermolysis of 1 yields trimethylsilyl fluoride, 6, and difluorooxathirane dioxide, 7, as primary products.The photoelectron spectra of 1, 2, 3, 6, and trimethylsilanol, 9, are presented.Molecular orbital eigenvalues of dimethylsilene, 4, dimethylsilanone, 5, (calculated using AMPAC and Gaussian 82), 6 and 9 (AMPAC) are reported.Molecular orbital contour diagrams are given for selected MOs of 6 and 9.
- Werstiuk, Nick Henry,Brook, Michael A.,Huelser, Peter
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p. 1430 - 1439
(2007/10/02)
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- Method for the simultaneous preparation of carboxylic acid trimethylsilyl esters and silylated carboxylic acid amides
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Carboxylic acid trimethylsilyl esters (I) and trimethylsilyl carboxylic acid amides can be prepared simultaneously from the corresponding carboxylic acid anhydrides; the esters (I) and monocarboxylic acid trimethylsilyl amides are formed first and can then be recovered, or else the bis-trimethylsilyl carboxylic acid amides are formed by further transposition with trimethylchlorosilane in the presence of tertiary amines, and are separated from the carboxylic acid trimethylsilyl ester (I) and recovered.
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- CLEAVAGES OF SILICON-CARBON BONDS IN TRIS(TRIMETHYLSILYL)METHYLSILICON COMPOUNDS BY TRIFLUOROACETIC ACID. REARRANGEMENTS AND ANCHIMERIC ASSISTANCE
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The fairly high rate of the highly sterically hindered compound (Me3Si)3CSiMe2Ph with CF3CO2H is consistent with the view that the rate-determining step involves the transfer of a proton from the acid to the ipso-carbon atom of the ring.The formation of the rearranged species (Me3Si)2C(SiMe2F)(SiMe2O2CCF3) in the reaction of (Me3Si)3CSiPhMeF with CF3CO2H suggests that the leaving of benzene from the initial protonated species generates a methyl-bridged silicon cation.Treatment of (Me3Si)3CSiPhMel with AgO2CCF3-CF3CO2H gives the rearranged (Me3Si)2C(SiPhMe2)(SiMe2O2CCF3), which reacts with CF3CO2H under reflux to give (Me3Si)2C(SiMe2O2CCF3)2.In remarkable example of anchimeric assistance by a γ-OMe group the compound (Me3Si)3CSiMe2OMe reacts readily with CF3CO2H at room temperature with evolution of methane, and formation finally of (Me3Si)2C(SiMe2O2CCF3)2, apparently via (Me3Si)2C(SiMe2OMe)(SiMe2O2CCF3).Sulphuric acid reacts very vigorously with (Me3Si)3CSiMe2OMe, and hydrolysis of the initial product gives the diol (Me3Si)3C(SiMe2OH)2.This diol can also be obtained by hydrolysis of (Me3Si)2C(SiMe2O2CCF3)2.
- Eaborn, Colin,Lickiss, Paul D.,Ramadan, Nazmi A.
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p. 267 - 270
(2007/10/02)
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- Perfluorocarboxylato disulfides and methylsilanes
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The reaction of disulfur dichloride, S2Cl2, with silver perfluorocarboxylates gives substituted disulfides, (RfCO2S)2, where Rf = CF3, C2F5, C3F
- Wang, Charlene S.,Pullen, Kent E.,Shreeve, Jean'ne M.
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