Lewis acid catalysis in a supercritical carbon dioxide (scCO2)-poly(ethylene glycol) derivatives (PEGs) system: remarkable effect of PEGS as additives on reactivity of Ln(OTf)3-catalyzed Mannich and aldol reactions in scCO2
Three-component Mannich-type reactions were efficiently catalyzed by hydrophobic polystyrene-supported sulfonic acid (PS–SO3H) in water as the sole solvent under mild conditions.
Ln(OTf)<sub>3</sub>- or Cu(OTf)<sub>2</sub>-Catalyzed Mannich-Type Reactions of Aldhehydes, Amines and Silyl Enolates in Micellar Systems. Facile Synthesis of β-Amino Ketones and Esters in Water
In the presence of a catalytic amount of Ln(OTf)3 or Cu(OTf)2, three-component Mannich-typereactions of aldehydes, amines, and silylenolates proceeded smoothly in micellar systems to afford the corresponding β-amino ketones or esters in high yields. These reactions were successfully carried out in water without using any organic solvents.
Lewis Acid Catalysis in Supercritical Carbon Dioxide. Use of Poly(ethylene glycol) Derivatives and Perfluoroalkylbenzenes as Surfactant Molecules Which Enable Efficient Catalysis in ScCO<sub>2</sub>
作者:Ichiro Komoto、Shū Kobayashi
DOI:10.1021/jo0353177
日期:2004.2.1
Lewis acid catalysis in supercritical carbon dioxide (CO2) was investigated. While solubility of most organic materials is low in scCO(2), poly(ethylene glycol) derivatives or perfluoroalkylbenzenes were found to work as surfactants to dissolve organic materials in scCO(2). In the presence of these molecules, Lewis acid catalyzed organic reactions such as aldol-, Mannich-, and Friedel-Crafts-type reactions proceeded smoothly in scCO(2). Formation of emulsions was observed in these reactions, and the systems were studied in detail.
Three-component carbon–carbon bond-forming reactions catalyzed by a Brønsted acid–surfactant-combined catalyst in water
作者:Kei Manabe、Yuichiro Mori、Shū Kobayashi
DOI:10.1016/s0040-4020(01)00081-3
日期:2001.3
Reactions of aldehydes, amines, and various nucleophiles such as silyl enolates, ketones, Danishefsky's diene, and allyltribuyltin in water were successfully carried out in the presence of p-dodecylbenzenesulfonic acid (DBSA) as a Bronsted acid-surfactant-combined catalyst. (C) 2001 Elsevier Science Ltd. All rights reserved.