2456-28-2Relevant academic research and scientific papers
Breaking C-O Bonds with Uranium: Uranyl Complexes as Selective Catalysts in the Hydrosilylation of Aldehydes
Monsigny, Louis,Thuéry, Pierre,Berthet, Jean-Claude,Cantat, Thibault
, p. 9025 - 9033 (2019/10/02)
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.
Effect of Alcohol Structure on the Kinetics of Etherification and Dehydration over Tungstated Zirconia
Rorrer, Julie,Pindi, Suresh,Toste, F. Dean,Bell, Alexis T.
, p. 3104 - 3111 (2018/09/06)
Linear and branched ether molecules have attracted recent interest as diesel additives and lubricants that can be produced from biomass-derived alcohols. In this study, tungstated zirconia was identified as a selective and green solid acid catalyst for the direct etherification of primary alcohols in the liquid phase, achieving ether selectivities of >94 % for C6–C12 linear alcohol coupling at 393 K. The length of linear primary alcohols (C6–C12) was shown to have a negligible effect on apparent activation energies for etherification and dehydration, demonstrating the possibility to produce both symmetrical and asymmetrical linear ethers. Reactions over a series of C6 alcohols with varying methyl branch positions indicated that substituted alcohols (2°, 3°) and alcohols with branches on the β-carbon readily undergo dehydration, but alcohols with branches at least three carbons away from the -OH group are highly selective to ether. A novel model compound, 4-hexyl-1dodecanol, was synthesized and tested to further demonstrate this structure–activity relationship. Trends in the effects of alcohol structure on selectivity were consistent with previously proposed mechanisms for etherification and dehydration, and help to define possible pathways to selectively form ethers from biomass-derived alcohols.
Antimony(v) cations for the selective catalytic transformation of aldehydes into symmetric ethers, α,β-unsaturated aldehydes, and 1,3,5-trioxanes
Arias Ugarte, Renzo,Devarajan, Deepa,Mushinski, Ryan M.,Hudnall, Todd W.
supporting information, p. 11150 - 11161 (2016/07/20)
1-Diphenylphosphinonaphthyl-8-triphenylstibonium triflate ([2][OTf]) was prepared in excellent yield by treating 1-lithio-8-diphenylphosphinonaphthalene with dibromotriphenylstiborane followed by halide abstraction with AgOTf. This antimony(v) cation was found to be stable toward oxygen and water, and exhibited exceptional Lewis acidity. The Lewis acidity of [2][OTf] was exploited in the catalytic reductive coupling of a variety of aldehydes into symmetric ethers of type L in good to excellent yields under mild conditions using Et3SiH as the reductant. Additionally, [2][OTf] was found to selectively catalyze the Aldol condensation reaction to afford α-β unsaturated aldehydes (M) when aldehydes with 2 α-hydrogen atoms were used. Finally, [2][OTf] catalyzed the cyclotrimerization of aliphatic and aromatic aldehydes to afford the industrially-useful 1,3,5 trioxanes (N) in good yields, and with great selectivity. This phosphine-stibonium motif represents one of the first catalytic systems of its kind that is able to catalyze these reactions with aldehydes in a controlled, efficient manner. The mechanism of these processes has been explored both experimentally and theoretically. In all cases the Lewis acidic nature of the antimony(v) cation was found to promote these reactions.
Copper(II) triflate-catalyzed reduction of carboxylic acids to alcohols and reductive etherification of carbonyl compounds
Zhang, Yin-Jie,Dayoub, Wissam,Chen, Guo-Rong,Lemaire, Marc
experimental part, p. 7400 - 7407 (2012/09/10)
A protocol is described for the reduction of carboxylic acids to primary alcohols using 1,1,3,3-tetramethyldisiloxane (TMDS) and a catalytic amount of Cu(OTf)2. Aliphatic as well as aromatic carboxylic acids are reduced in high selectivity and good yields. TMDS/Cu(OTf)2 has also been found to be an efficient catalytic reducing system for the preparation of symmetrical ethers from carbonyl compounds under mild conditions.
The continuous acid-catalysed etherification of aliphatic alcohols using stoichiometric quantities of dialkyl carbonates
Parrott, Andrew J.,Bourne, Richard A.,Gooden, Peter N.,Poliakoff, Martyn,Irvine, Derek J.,Bevinakatti, Han. S.
supporting information; experimental part, p. 1420 - 1426 (2011/09/20)
A range of methyl and ethyl ethers of aliphatic alcohols have been synthesized cleanly in high yield by reacting the corresponding alcohol with dimethyl carbonate or diethyl carbonate over the solid acid catalyst, I-alumina. The reaction could be conducted at ambient pressure without the need for the large excess of dialkyl carbonate as previously reported in the literature. If the reaction was conducted at high pressure, the conversion of the starting alcohol was greatly reduced. However, high pressure CO2 can be used as the solvent without significant reduction in yield. This has implications for tandem reactions.
Method of increasing the carbon chain length of olefinic compounds
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Page/Page column 3, (2008/06/13)
According to the present invention there is provided a process of increasing the carbon chain length of an olefinic compound comprising the steps of providing a starting olefinic compound and subjecting it to hydroformylation to produce an aldehyde and/or alcohol with an increased carbon chain length compared to the starting olefinic compound. Optionally, the aldehyde that may form during the hydroformylation reaction is hydrogenated to convert it to an alcohol which has an increased carbon chain length compared to the starting olefinic compound. The alcohol with the increased carbon chain length is subjected to dehydration to produce an olefinic compound with an increased carbon chain length compared to the starting olefinic compound. The invention also relates to olefinic compounds produced by the process.
Conversion of alkyl halides into alcohols via formyloxylation reaction with DMF catalyzed by silver salts
Abad, Antonio,Agullo, Consuelo,Cunat, Ana C.,Navarro, Ismael
, p. 3355 - 3361 (2007/10/03)
The transformation of alkyl halides into alcohols via a two-step process based on the reaction with DMF catalyzed by Ag(I) salts followed by acid or basic hydrolysis of the intermediate formate ester has been evaluated. The results show that a large variety of primary and some secondary alkyl halides can be transformed efficiently into the corresponding alcohols, making this alkyl halide to alcohol interconversion a valuable alternative to the existing procedures, particularly in molecules with labile functional groups that are generally involved in multistep synthesis. Georg Thieme Verlag Stuttgart.
Synthesis of 2,2′-quinocyanines with long N-alkyl substituents
Orlova,Kolchina,Zhuravlev,Shakirov,Gerasimova,Shelkovnikov
, p. 1233 - 1241 (2007/10/03)
2,2′-Quinocyanines with long alkyl substituents on one or both nitrogen atoms have been synthesized. 1H NMR spectroscopy has been used to study the processes occurring during the alkylation of the starting quinoline bases.
Process for producing ether compound
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, (2008/06/13)
Ether compounds, which are useful as solvents, cosmetics, detergents, lubricants, emulsifiers and so on, are produced by reacting (a) a hydroxy compound with a carbonyl compound of (b) a carbonyl compound under hydrogen atmosphere in the presence of a catalyst with ease and at a low cost. The reaction is carried out while removing out produced water by using a dehydrating agent during the reaction; by distilling off the water by azeotropic dehydration and the like; or by blowing gases such as hydrogen gas to flow through the reaction system.
