62572-35-4Relevant academic research and scientific papers
The Mukaiyama aldol and Mukaiyama-Michael reactions promoted by commercially available molecular sieves
Anada, Masahiro,Washio, Takuya,Watanabe, Yudai,Hashimoto, Shunichi
experimental part, p. 1489 - 1503 (2010/10/20)
The Mukaiyama aldol reaction of silyl ketene acetals with aldehydes has been effected by using commercially available 4 molecular sieves (4 MS) as a promoter. Various silyl ketene acetals and silyl enol ethers have been shown to be effective nucleophiles
Cationic iridium complex is a new and efficient Lewis acid catalyst for aldol and Mannich reactions
Onodera, Gen,Toeda, Takayuki,Toda, Nou-No,Shibagishi, Daigo,Takeuchi, Ryo
experimental part, p. 9021 - 9031 (2011/01/04)
A cationic iridium complex [Ir(cod)2]SbF6 was found to be a new and efficient Lewis acid catalyst for Mukaiyama aldol and Mannich reactions. Aldehydes react smoothly with silyl enol ethers to give β-siloxy ketones in the presence of 0.5 mol % of [Ir(cod)2]SbF6. The reaction of N-alkyl arylaldimines with ketene silyl acetals in the presence of 5 mol % [Ir(cod)2]SbF6/P(OPh)3 gave β-amino esters. After Mannich reaction was complete, stirring of the reaction mixture for 24 h led to cyclization to give β-lactam. The reaction of N-aryl benzaldimine with silyl enol ether derived from acetophenone gave a tetrahydroquinoline derivative as a single diastereomer.
ScIII-Doped zeolites as new heterogeneous catalysts: mukaiyama aldol reaction
Olmos, Andrea,Alix, Aurelien,Sommer, Jean,Pale, Patrick
supporting information; experimental part, p. 11229 - 11234 (2010/04/28)
ScIII-doped solids based on zeolite materials have been investigated for the first time as catalysts in organic synthesis. Sc III-USY zeolite proved to be a novel and very efficient heterogeneous catalyst for the Mukaiyama aldol reaction. This easy-to-prepare catalyst exhibited wide scope and compatibility with functional groups and is very simple to use, easy to remove (by simple filtration), and is recyclable (up to three times without loss of activity).
Mukaiyama aldol reaction catalyzed by mesoporous aluminosilicate
Ito, Suguru,Yamaguchi, Hitoshi,Kubota, Yoshihiro,Asami, Masatoshi
experimental part, p. 700 - 701 (2011/04/21)
In the presence of a mesoporous aluminosilicate Al-MCM-41, aldol reaction of various silyl enol ethers with both aromatic and aliphatic aldehydes proceeded under mild reaction conditions to afford the corresponding O-silylated aldol adducts in high yields. The solid acid catalyst was easily recovered and reusable three times. Copyright
Acid-base catalyses by dimeric disilicoicosatungstates and divacant γ-Keggin-type silicodecatungstate parent: Reactivity of the polyoxometalate compounds controlled by step-by-step protonation of lacunary W{double bond, long}O sites
Yoshida, Akihiro,Hikichi, Shiro,Mizuno, Noritaka
, p. 455 - 459 (2008/02/06)
The catalytic properties of disilicoicosatungstates, [{γ-SiW10O32(H2O)2}2(μ-O)2]4- (2) and [H(γ-SiW10O32)2(μ-O)4]7- (3), and their parent divacant γ-Keggin type silicodecatungstate, [γ-SiW10O34(H2O)2]4- (1), toward C-C bond formation reactions have been investigated. The disilicoicosatungstate 2 with aquo ligands exhibits the acidic nature and catalyzes the Mukaiyama-aldol condensation and carbonyl-ene reaction, while 1 and 3 are rather basic and catalyze the Knoevenagel condensation. Therefore, the acid-base properties of a series of lacunary γ-Keggin silicotungstate derivatives 1-3 are clearly different, and the catalyses of 1-3 depend on the molecular structures while 1-3 are composed of a common [SiW10O32] fragment.
Crucial role of the conjugate base for silyl Lewis acid induced Mukaiyama aldol reactions
Hiraiwa, Yukihiro,Ishihara, Kazuaki,Yamamoto, Hisashi
, p. 1837 - 1844 (2007/10/03)
The silyl Lewis acid induced Mukaiyama aldol reaction proceeds through each catalytic cycle under the influence of their conjugate bases; there is an especially significant difference between the low nucleophilic conjugate bases, -NTf2 and -CTf3, and the relatively high nucleophilic -OTf. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
Yb(OTf)3-TMSCl, a novel catalytic system in cross-aldol reactions
Kagawa, Natsuko,Toyota, Masahiro,Ihara, Masataka
, p. 655 - 657 (2007/10/03)
A combination of Yb(OTf)3 and TMSCl influenced the outcome of cross-aldol reactions of cycloalkanones and benzaldehyde. Interestingly, reaction of cycloheptanone and cyclooctanone with aldehydes under the Yb(OTf)3- TMSCl reagent system provides 3-(2-oxocycloalkyl)-3- phenylpropanals in conjunction with the corresponding aldol products.
Crucial role of the ligand of silyl Lewis acid in the Mukaiyama aldol reaction
Ishihara, Kazuaki,Hiraiwa, Yukihiro,Yamamoto, Hisashi
, p. 1564 - 1565 (2007/10/03)
The Me3SiX-induced Mukaiyama aldol reaction proceeds through each catalytic cycle under the influence of X-: the silyl group of Me3SiNTf2 does not release from -NTf2 and that of silyl enol ether intermolecularly transfers to the product, while the silyl group of Me3SiOTf remains in the product and that of the silyl enol ether becomes the catalyst for the next catalytic cycle.
Clay montmorillonite K10 catalyzed aldol-type reaction of aldehydes with silyl enol ethers in water
Loh, Teck-Peng,Li, Xu-Ran
, p. 10789 - 10802 (2007/10/03)
An environmentally friendly method for the cross aldol reaction of silyl enol ethers and ketene silyl acetal with various aldehydes using montmorillonite K10 is described. Cheap and commercially available montmorillonite K10 can be used without the need of an ion exchange process under solvent-free conditions or in water. Hydrate of aldehydes such as glyoxylic acid can be used directly. Thermal treatment of K10 increased the catalytic activity. The catalytic activity was supposed due to the properties of the structure of K10 and its inherent Bronsted acidity.
Chemoselective aldol condensation in 5 mol dm 3 lithium perchlorate-nitromethane. A comparison with lithium perchloratediethyl ether medium
Sudha,Sankararaman
, p. 383 - 386 (2007/10/03)
Aldol reactions of silyl enol ethers with aldehydes proceed in 5 mol dm 3 lithium perchlorate-nitromethane medium at ambient temperature. The reaction is highly chemoselective such that only aldehydes and cyclic ketones reacted while acyclic and aromatic ketones failed to react. The same reaction is not promoted in 5 mol dm"3 lithium perchlorate-diethyl ether medium. The difference between these two media is explained by the increased Lewis acidity of the lithium ion in nitromethane compared to that in ether.
