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Prochiral Olefins (prochiral + olefin)

Distribution by Scientific Domains
Chemistry100%
Distribution within Chemistry
Organic Chemistry66%
General & Introductory Chemistry33%

Selected Abstracts

Rh-Catalyzed Asymmetric Hydrogenation of Prochiral Olefins with a Dynamic Library of Chiral TROPOS Phosphorus Ligands.

CHEMINFORM, Issue 14 2006
Chiara Monti
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]

Furanoside Diphosphinites as Suitable Ligands for the Asymmetric Catalytic Hydrogenation of Prochiral Olefins.

CHEMINFORM, Issue 49 2004
Eugeni Guimet
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Lewis Acid Activated Chiral Leaving Group: Enantioselective Electrophilic Addition to Prochiral Olefins.

CHEMINFORM, Issue 3 2003
Hiroko Nakamura
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Asymmetric Hydrogenations (Nobel Lecture 2001)

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1-2 2003
William
Abstract The start of the development of catalysts for asymmetric hydrogenation was the concept of replacing the triphenylphosphane ligand of the Wilkinson catalyst with a chiral ligand. With the new catalysts, it should be possible to hydrogenate prochiral olefins. Knowles and his co-workers were convinced that the phosphorus atom played a central role in this selectivity, as only chiral phosphorus ligands such as (R,R)-DIPAMP, whose stereogenic center lies directly on the phosphorus atom, lead to high enantiomeric excesses when used as catalysts in asymmetric hydrogenation reactions. This hypothesis was disproven by the development of ligands with chiral carbon backbones. Although the exact mechanism of action of the phosphane ligands is not incontrovertibly determined to this day, they provide a simple entry to a large number of chiral compounds. [source]

Asymmetric Hydrogenation with Highly Active IndolPhos,Rh Catalysts: Kinetics and Reaction Mechanism

CHEMISTRY - A EUROPEAN JOURNAL, Issue 22 2010
Jeroen Wassenaar
Abstract The mechanism of the IndolPhos,Rh-catalyzed asymmetric hydrogenation of prochiral olefins has been investigated by means of X-ray crystal structure determination, kinetic measurements, high-pressure NMR spectroscopy, and DFT calculations. The mechanistic study indicates that the reaction follows an unsaturate/dihydride mechanism according to Michaelis,Menten kinetics. A large value of KM (KM=5.01±0.16,M) is obtained, which indicates that the Rh,solvate complex is the catalyst resting state, which has been observed by high-pressure NMR spectroscopy. DFT calculations on the substrate,catalyst complexes, which are undetectable by experimental means, suggest that the major substrate,catalyst complex leads to the product. Such a mechanism is in accordance with previous studies on the mechanism of asymmetric hydrogenation reactions with C1 -symmetric heteroditopic and monodentate ligands. [source]

Trinuclear Rhodium Complexes and Their Relevance for Asymmetric Hydrogenation

CHEMISTRY - AN ASIAN JOURNAL, Issue 11 2008
Angelika Preetz
Abstract Various trinuclear rhodium complexes of the type [Rh3(PP)3(,3 -OH)x(,3 -OMe)2,x]BF4 (where PP=Me-DuPhos, dipamp, dppp, dppe; different ligands and , -bridging anions) are presented, which are formed upon addition of bases such as NEt3 to solvate complexes [Rh(PP)(solvent)2]BF4. They were extensively characterized by X-ray diffraction and NMR spectroscopy (103Rh, 31P, 13C, 1H). Their in,situ formation resulting from basic additives (NEt3) or basic prochiral olefins (without addition of another base) can cause deactivation of the asymmetric hydrogenation. This effect can be reversed by means of acidic additives. [source]