17488-65-2Relevant articles and documents
An efficient heterogeneous catalytic system for chemoselective hydrogenation of unsaturated ketones in aqueous medium
Deshmukh, Amit,Kinage, Anil,Kumar, Rajiv,Meijboom, Reinout
, p. 3262 - 3268 (2010)
A highly chemoselective and green heterogeneous catalytic system of immobilized Ru(II)-phenanthroline complexes on amino functionalised MCM-41 material for the chemoselective hydrogenation of unsaturated ketones to unsaturated alcohols is demonstrated using water as a solvent. The XRD and FTIR spectra show the highly ordered hexagonal nature of the MCM-41, even after encapsulation of the ruthenium complex. The complex retains its configuration after anchoring, as was confirmed by FTIR and UV-Vis analysis. The detailed reaction parametric effect was studied for the hydrogenation of 3-methylpent-3-en-2-one to achieve complete conversion up to >99% chemoselectivity of 3-methylpent-3-en-2-ol. The anchored heterogeneous catalysts were recycled effectively and reused five times with marginal changes in activity and selectivity. The use of water as a solvent not only afforded high activity for the hydrogenation reaction compared to organic solvents, but also afforded a green process.
Comparison of the Catalytic Properties of 25-Atom Gold Nanospheres and Nanorods
Zhu, Yan,Qian, Huifeng,Das, Anindita,Jin, Rongchao
, p. 1149 - 1155 (2011)
The catalytic properties of two nanocluster catalysts with atomically precisely known structures, icosahedral two-shelled Au25(SC2H4Ph)18 nanospheres and biicosahedral Au25(PPh3)10(SC2H4Ph)5Cl2 nanorods, were compared. Their catalytic performance in the two reactions of the selective oxidation of styrene and chemoselective hydrogenation of α,β-unsaturated benzalacetone was investigated. The catalytic activities of icosahedral Au25(SC2H4Ph)18 nanospheres were superior to those of the bi-icosahedral Au25(PPh3)10(SC2H4Ph)5Cl2 nanorods for both reactions. The better catalytic performance of the Au25(SC2H4Ph)18 nanospheres can be attributed to their unique core-shell (Au13/Au12) geometric structure that has an open exterior atomic shell and to their electronic structure with an electron-rich Au13 core and an electron-deficient Au12 shell.
Disproportionation of acyclic ketones to carboxylate ions and ethers: A poisoning reaction on the way to the chemoselective reduction of α,β, -unsaturated ketones to allylic alcohols via hydrogen-transfer catalysed by a nonclassical ruthenium(II) trihydride
Bianchini,Farnetti,Frediani,Graziani,Peruzzini,Polo
, p. 1336 - 1337 (1991)
-
Mechanochemical, Water-Assisted Asymmetric Transfer Hydrogenation of Ketones Using Ruthenium Catalyst
Kolcsár, Vanessza Judit,Sz?ll?si, Gy?rgy
, (2022/01/04)
Asymmetric catalytic reactions are among the most convenient and environmentally benign methods to obtain optically pure compounds. The aim of this study was to develop a green system for the asymmetric transfer hydrogenation of ketones, applying chiral Ru catalyst in aqueous media and mechanochemical energy transmission. Using a ball mill we have optimized the milling parameters in the transfer hydrogenation of acetophenone followed by reduction of various substituted derivatives. The scope of the method was extended to carbo- and heterocyclic ketones. The scale-up of the developed system was successful, the optically enriched alcohols could be obtained in high yields. The developed mechanochemical system provides TOFs up to 168 h?1. Our present study is the first in which mechanochemically activated enantioselective transfer hydrogenations were carried out, thus, may be a useful guide for the practical synthesis of optically pure chiral secondary alcohols.
Overcoming Kinetic and Thermodynamic Challenges of Classic Cope Rearrangements
Fereyduni, Ehsan,Lahtigui, Ouidad,Sanders, Jacob N.,Tomiczek, Breanna M.,Mannchen, Michael D.,Yu, Roland A.,Houk,Grenning, Alexander J.
, p. 2632 - 2643 (2021/02/05)
Systematic evaluation of 1,5-dienes bearing 3,3-electron-withdrawing groups and 4-methylation results in the discovery of a Cope rearrangement for Meldrum's acid-containing substrates that have unexpectedly favorable kinetic and thermodynamic profiles. The protocol is quite general due to a concise and convergent synthesis from abundant starting materials. Furthermore, products with an embedded Meldrum's acid moiety are prepared, which, in turn, can yield complex amides under neutral conditions. We have now expanded the scope of the reductive Cope rearrangement, which, via chemoselective reduction, can promote thermodynamically unfavorable [3,3] sigmatropic rearrangements of 3,3-dicyano-1,5-dienes to form reduced Cope rearrangement products. The Cope rearrangement is found to be stereospecific and can yield enantioenriched building blocks when chiral, nonracemic 1,3-disubstituted allylic electrophiles are utilized. We expand further the use of Cope rearrangements for the synthesis of highly valuable building blocks for complex- and drug-like molecular synthesis.
