- Bis(perfluoropinacolato)silane: A Neutral Silane Lewis Superacid Activates Si?F Bonds
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Despite the earth abundance and easy availability of silicon, only few examples of isolable neutral silicon centered Lewis superacids are precedent in the literature. To approach the general drawbacks of limited solubility and unselective deactivation pathways, we introduce a Lewis superacid, based on perfluorinated pinacol substituents. The compound is easily synthesized on a gram-scale as the corresponding acetonitrile mono-adduct 1?(MeCN) and was fully characterized, including single crystal X-ray diffraction analysis (SC-XRD) and state-of-the-art computations. Lewis acidity investigations by the Gutmann-Beckett method and fluoride abstraction experiments indicate a Lewis superacidic nature. The challenging Si?F bond activation of Et3SiF is realized and promising catalytic properties are demonstrated, consolidating the potential applicability of silicon centered Lewis acids in synthetic catalysis.
- Greb, Lutz,Hanusch, Franziska,Inoue, Shigeyoshi,Thorwart, Thadd?us,Tschernuth, Florian S.
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supporting information
p. 25799 - 25803
(2021/11/09)
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- Breaking C-O Bonds with Uranium: Uranyl Complexes as Selective Catalysts in the Hydrosilylation of Aldehydes
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We report herein the possibility to perform the hydrosilylation of carbonyls using actinide complexes as catalysts. While complexes of the uranyl ion [UO2]2+ have been poorly considered in catalysis, we show the potentialities of the Lewis acid [UO2(OTf)2] (1) in the catalytic hydrosilylation of a series of aldehydes. [UO2(OTf)2] proved to be a very active catalyst affording distinct reduction products depending on the nature of the reductant. With Et3SiH, a number of aliphatic and aromatic aldehydes are reduced into symmetric ethers, while iPr3SiH yielded silylated alcohols. Studies of the reaction mechanism led to the isolation of aldehyde/uranyl complexes, [UO2(OTf)2(4-Me2N-PhCHO)3], [UO2(μ-κ2-OTf)2(PhCHO)]n, and [UO2(μ-κ2-OTf)(κ1-OTf)(PhCHO)2]2, which have been fully characterized by NMR, IR, and single-crystal X-ray diffraction.
- Monsigny, Louis,Thuéry, Pierre,Berthet, Jean-Claude,Cantat, Thibault
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p. 9025 - 9033
(2019/10/02)
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- Synthesis of ethers from carbonyl compounds by reductive etherification catalyzed by iron(III) and silyl chloride
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A simple iron- and silyl chloride catalyzed method for the preparation of symmetrical and nonsymmetrical ethers is presented. Various aldehydes and ketones were reductively etherified by using triethylsilane as a reducing agent in the presence of 2 mol% of iron(III) oxo acetate and 8 mol% of chloro(trimethyl)silane. The reactions can be carried out at ambient temperatures and pressures with ethyl acetate as the solvent.
- Savela, Risto,Leino, Reko
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p. 1749 - 1760
(2015/06/16)
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- Zinc-catalyzed reduction of aldehydes with a hydrosilane leading to symmetric ethers and silyl ethers
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The efficient reductive etherification of aromatic or aliphatic aldehydes using a reducing system that combines Zn(OTf)2 with either TMDS or Et3SiH is described. The present reducing system can also be applied to the hydrosilylation of aromatic aldehydes having either a strong electron-withdrawing group or a pyridine ring.
- Sakai, Norio,Nonomura, Yoshifumi,Ikeda, Reiko,Konakahara, Takeo
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p. 489 - 491
(2013/06/26)
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- Reactions of Thianthrene Cation Radical with Acyclic and Cyclic Alcohols
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Thianthrene cation radical perchlorate (Th(.+)*ClO4(-)) reacted readily with cycloalkanols (C5, C7, C8, and C12), alkan-2-ols (C3, C5, C6, and C8), 3-hexanol, neopentyl alcohol, a number of benzyl alcohols, dl- and (S)-1-phenylethanol, cyclopentyl- and cyclohexylmethanols, the exo- and endo-borneols, and norborneols.Reactions were carried out with an excess of the alcohol in acetonitrile solution containing 2,6-di-tert-butyl-4-methylpyridine.Products were alkenes, ethers, and N-substituted acetamides, depending on the structure of the alcohol.Thianthrene (Th) and its 5-oxide (ThO) were formed in equal amounts.The sum of amounts of products from the alcohol was equal to the amount of ThO.All reactions are interpretable on the basis of the ultimate formation and further reactions of a 5-alkoxythianthreniumyl ion (ROTh(+)).The predominant formation of nortricyclene from the norborneols is striking and is discussed.Swern-Moffatt-type oxidations of the alcohols were not observed.
- Shine, Henry J.,Yueh, Wang
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p. 3553 - 3559
(2007/10/02)
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- Method of preparing arylacetic acid alkyl esters
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In a process of producing an alkyl ester of a substituted or unsubstituted arylacetic acid wherein a substituted or unsubstituted aromatic halogen methyl compound is reacted with carbon monoxide and an alcohol having an alkoxy group the same as that of said ester, the improvement which comprises carrying out said reaction in a basic reaction medium in the presence as catalyst of: A. cobalt salt, metal or metal alloy and a sulfur compound, or B. a metal carbonyl compound.
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