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Various Ketones (various + ketone)

Distribution by Scientific Domains
Chemistry100%
Distribution within Chemistry
Organic Chemistry60%
General & Introductory Chemistry40%

Selected Abstracts

Novel Fluorous Prolinol as a Pre-Catalyst for Catalytic Asymmetic Borane Reduction of Various Ketones.

CHEMINFORM, Issue 33 2007
Sakiko Goushi
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

Synthesis of Ruthenium Hydride Complexes Containing beta-Aminophosphine Ligands Derived from Amino Acids and their use in the H2 -Hydrogenation of Ketones and Imines

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4 2005
Kamaluddin Abdur-Rashid
Abstract The new complexes RuHCl(PPh2CH2CHRNH2)2 and RuHCl(PPh2CH2CHRNH2)(R- binap), R=H (Pgly), R=Me [(R)-Pala] were prepared by the substitution of the PPh3 ligands in RuHCl(PPh3)3 or RuHCl(PPh3)[(R)-binap] with beta-aminophosphines derived from amino acids. The complex trans -RuHCl(Pgly)[(R)-binap] has been characterized by X-ray crystallography. The complex trans -RuHCl[(S)-Ppro]2 where (S)-Ppro is derived from proline was also prepared and characterized by X-ray crystallography. These were used as catalyst precursors in the presence of a base (KOPr- i or KOBu- t) for the hydrogenation of various ketones and imines to the respective alcohols and amines with H2 gas (1,11 atm) at room temperature. Acetophenone was hydrogenated to (S)-1-phenylethanol in low ee (up to 40%) when catalyzed by the enantiomerically pure complexes. These complexes are especially active in the hydrogenation of sterically congested and electronically deactivated ketones and imines and are selective for the hydrogenation of CO bonds over CC bonds. [source]

Lewis Base Catalyzed Mannich-Type Reactions between Trimethylsilyl Enol Ethers and Aldimines

CHEMISTRY - A EUROPEAN JOURNAL, Issue 19 2006
Hidehiko Fujisawa
Abstract Lewis base catalyzed Mannich-type reaction between trimethylsilyl enol ethers and N -tosylaldimines is described. Nitrogen anions generated from amides or imides such as lithium benzamide or potassium phthalimide are found to be effective Lewis base catalysts in DMF at room temperature to afford the corresponding ,-amino carbonyl compounds in good to high yields; the oxygen anion generated from carboxylic acids such as lithium acetate was also found to be effective in dry DMF. The above-mentioned lithium acetate-catalyzed Mannich-type reaction between aldimines and various trimethylsilyl (TMS) enol ethers such as silyl ketene acetal proceeded smoothly even in water-containing DMF. Then, Lewis base catalyzed three-component Mannich-type reactions of TMS enol ether, tosylamide, and aromatic aldehyde having electron-withdrawing group such as p -nitrobenzaldehyde were investigated. The reaction proceeded smoothly to afford the corresponding ,-amino ester in good yield. Further, ammonium carboxylates such as tetrabutyl ammonium acetate or tetrabutyl ammonium benzoate were found to be more effective Lewis base catalysts in the above-mentioned Mannich-type reaction. The synthesis proceeded in various solvents at lower temperatures. The reaction between aldimines and TMS enol ethers generated from thioester and various ketones such as propiophenone or cyclohexanone also proceeded smoothly to afford the corresponding ,-amino carbonyl compounds in high yields with good to high anti -selectivities. [source]

Facile and Efficient Reduction of Ketones in the Presence of Zinc Catalysts Modified by Phenol Ligands

CHEMISTRY - AN ASIAN JOURNAL, Issue 9 2010
Stephan Enthaler Dr.
Abstract In the present study, the zinc-catalyzed hydrosilylation of various ketones to give their corresponding alcohols has been examined in detail. Diethyl zinc that can be modified by easily accessible phenol ligands allows the efficient reduction of various aryl and alkyl ketones. By using a practical in situ catalyst, excellent turnover frequencies up to 1000,h,1 and a broad functional group tolerance were achieved. Im Rahmen dieser Arbeit wird die Zink-katalysierte Hydrosilylierung von Ketonen zu den entsprechenden Silylethern mit anschließender Hydrolyse zu deren Alkoholen vorgestellt. Wobei exzellente Ausbeuten und Umsätze durch die Modifikation des katalytisch eingesetzten Diethylzink mit Phenolen erreicht werden konnten. Nach genauer Untersuchung verschiedenster Reaktionsparameter konnten turnover frequencies (TOF) von ca. 1000,h,1 erzielt werden. Die hervorragenden Eigenschaften des Katalysatorsystems konnte weiterhin in der Hydrosilylierung verschiedenster Ketone erfolgreich gezeigt werden. Zum besseren Verständnis der Reaktion wurden verschiedene mechanistische Experimente durchgeführt. [source]

Enantioselective cyanosilylation of ketones catalyzed by recyclable polymeric and dimeric MN(III) salen complexes at room temperature

CHIRALITY, Issue 2 2009
Noor-Ul H. Khan
Abstract Recyclable polymeric 1 and dimeric 2 chiral Mn(III) salen complexes catalyzed enantioselective cyanosilylation of various ketones in the presence of triphenylphosphine oxide as an additive proceeded smoothly at room temperature, providing excellent yields (up to 98%) and enantiomeric excess (up to 86%) of respective cyanohydrin trimethylsilyl ether. For most of the substrates, the Catalyst 1 showed slightly better reactivity and enantioselecitivity than the Catalyst 2 nevertheless both the catalysts were easily recovered and reused four times with the retention of their efficiency. Chirality, 2009. © 2008 Wiley-Liss, Inc. [source]