32338-47-9Relevant articles and documents
Photocontrolled Cobalt Catalysis for Selective Hydroboration of α,β-Unsaturated Ketones
Beltran, Frédéric,Bergamaschi, Enrico,Funes-Ardoiz, Ignacio,Teskey, Christopher J.
supporting information, p. 21176 - 21182 (2020/09/17)
Selectivity between 1,2 and 1,4 addition of a nucleophile to an α,β-unsaturated carbonyl compound has classically been modified by the addition of stoichiometric additives to the substrate or reagent to increase their “hard” or “soft” character. Here, we demonstrate a conceptually distinct approach that instead relies on controlling the coordination sphere of a catalyst with visible light. In this way, we bias the reaction down two divergent pathways, giving contrasting products in the catalytic hydroboration of α,β-unsaturated ketones. This includes direct access to previously elusive cyclic enolborates, via 1,4-selective hydroboration, providing a straightforward and stereoselective route to rare syn-aldol products in one-pot. DFT calculations and mechanistic experiments confirm two different mechanisms are operative, underpinning this unusual photocontrolled selectivity switch.
Ion-Tagged Prolinamide Organocatalysts for the Direct Aldol Reaction On-Water
Eyckens, Daniel J.,Brozinski, Hannah L.,Delaney, Joshua P.,Servinis, Linden,Naghashian, Sahar,Henderson, Luke C.
, p. 212 - 219 (2016/02/23)
A concise synthesis of two imidazolium ion-tagged prolinamide organocatalysts 3 and 4, varying in anionic component (CF3COO- and PF6 -, respectively) is presented. The latter could be classified as an ionic liqu
Synthesis of sulphur-modified bifunctional hydrotalcites and study of their surface characteristics by inverse gas chromatography
Ren, Xiaoqian,Hu, Xi,Zhang, Feng,Wang, Junge,Liang, Jinhua,Wu, Wenliang,Jiang, Min,Wang, Jun
, p. 4813 - 4820 (2015/10/05)
In this study, various sulphur-modified hydrotalcite catalysts were prepared, and the influence of calcination temperature on their acid-base properties was investigated. Structural characterization of the catalysts was studied using X-ray powder diffraction, scanning electron microscopy, N2 physisorption, elemental analysis and Fourier transform infrared spectroscopy. The structural characterization indicated that the layer structure of all catalysts was retained but the specific surface areas were enlarged. Inverse gas chromatography was carried out to quantitatively determine the catalysts' acid-base properties by calculating the thermodynamic parameters, including dispersive surface free energy, adsorption free energy, adsorption enthalpy, and acid-base interaction constants. The results showed that the strength and content of acidic and alkaline sites were enhanced with increasing calcination temperature. Moreover, several typical aldol condensation reactions were selected to study the catalytic activity of the developed catalysts. The results showed that the sulphur-modified hydrotalcite catalysts possess high activity and good regenerability for typical aldol condensation reactions.
