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Asymmetric Activation (asymmetric + activation)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

Discovery of Chiral Catalysts by Asymmetric Activation for Highly Enantioselective Diethylzinc Addition to Imines: Using Racemic and Achiral Diimines as Effective Activators.

CHEMINFORM, Issue 3 2006
Hua Liu
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

ChemInform Abstract: Asymmetric Activation of Conformationally Flexible Monodentate Phosphites for Enantioselective Hydrogenation.

CHEMINFORM, Issue 9 2002
Weiping Chen
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Engineering Chiral Catalysts through Asymmetric Activation and Super High Throughput Screening (SHTS)

CHINESE JOURNAL OF CHEMISTRY, Issue 6 2001
Koichi Mkami
Abstract A conceptually new strategy for asymmetric catalysis, namely asymmetric activation, in which a chiral activator selectively activates one enantiomer of a racemic chiral catalyst, and a highly efficient screening system for finding the most effective catalysts, namely super high throughput screening (SHTS), by which the reaction can be conducted in parallel and the ee% of the product is allowed to determine within minutes, are summarized in the present account. It is reasonable to believe that SHTS technique combined with asymmetric activation or deactivation principle will provide a very powerful methodology for finding the new catalysts and the best catalyst tuning for asymmetric reactions. [source]

Asymmetric Activation/Deactivation of Racemic Ru Catalysts for Highly Enantioselective Hydrogenation Irrespective of Ketonic Substrates: Molecular Design of Dimethylbinaphthylamine for Enantiomeric Catalysts Discrimination

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1-2 2003
Koichi Mikami
Abstract Asymmetric activation and deactivation of racemic catalysts are two extremes in asymmetric catalysis. In a combination of these two protocols, higher enantioselectivity can be achieved by maximizing the difference in catalytic activity between the enantiomers of racemic catalysts through selective activation and deactivation of enantiomeric catalysts. 3,3,-Dimethyl-2,2,-diamino-1,1,-binaphthyl (DM-DABN) is thus designed as a chiral poison (deactivator) for complete enantiomer resolution of racemic BINAP-Ru(II) catalysts. The catalyst system of DM-DABN, 1,2-diphenylethylenediamine (DPEN), and racemic BINAP-Ru(II) led to great success in highly enantioselective hydrogenation irrespective of the ketonic substrates. The lower catalytic activity of the BINAP-Ru(II)/DM-DABN complex stems from the electron delocalization from the Ru center to the diamine moiety in contrast to the BINAP-Ru(II)/DPEN complex where the highest electron densities are localized on the Ru-N region. The present ,asymmetric activation/deactivation protocol' can provide a guiding principle for the rational design of a molecule for enantiomeric discrimination between racemic catalysts. [source]

Engineering Chiral Catalysts through Asymmetric Activation and Super High Throughput Screening (SHTS)

CHINESE JOURNAL OF CHEMISTRY, Issue 6 2001
Koichi Mkami
Abstract A conceptually new strategy for asymmetric catalysis, namely asymmetric activation, in which a chiral activator selectively activates one enantiomer of a racemic chiral catalyst, and a highly efficient screening system for finding the most effective catalysts, namely super high throughput screening (SHTS), by which the reaction can be conducted in parallel and the ee% of the product is allowed to determine within minutes, are summarized in the present account. It is reasonable to believe that SHTS technique combined with asymmetric activation or deactivation principle will provide a very powerful methodology for finding the new catalysts and the best catalyst tuning for asymmetric reactions. [source]