Key role of the Lewis base position in asymmetric bifunctional catalysis: design and evaluation of a new ligand for chiral polymetallic catalysts.

Key role of the Lewis base position in asymmetric bifunctional catalysis: design and evaluation of a new ligand for chiral polymetallic catalysts. Research Abstract Details 

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Key role of the Lewis base position in asymmetric bifunctional catalysis: design and evaluation of a new ligand for chiral polymetallic catalysts. Abstract Text:

Ikuo Fujimori,Tsuyoshi Mita,Keisuke Maki,Motoo Shiro,Akihiro Sato,Sanae Furusho,Motomu Kanai,Masakatsu Shibasaki,

New chiral ligands for asymmetric polymetallic catalysts were designed on the basis of the assumption that the higher-order assembly structure is stabilized by modifying the modular unit. The designed ligands 6 and 7 contained a scaffolding cyclohexane ring with a Lewis base phosphine oxide directly attached to the scaffold. A module in the polymetallic complex contains two metals per ligand, and a stable 6-, 5-, 5-membered fused chelation ring system should be generated. Synthesis of these ligands is simple and high yielding, using a catalytic dynamic kinetic resolution promoted by the Trost catalyst as a key step. Ligand function was assessed in a catalytic asymmetric ring-opening reaction of meso-aziridines with TMSCN, a useful reaction for the synthesis of optically active beta-amino acids. The Gd complex generated from Gd(OiPr)3 and the ligand was a highly active and enantioselective catalyst in this reaction. Enantioselectivity was reversed compared to the previously reported d-glucose-derived catalyst containing the same chirality of the individual module. ESI-MS analysis and X-ray crystallographic studies indicate that the assembly state of the modules in the polymetallic catalysts differs depending on the chiral ligand. The difference in the higher-order structure stems from a subtle change (one carbon) in the position of the Lewis base relative to the Gd metal. The change in the higher-order structure of the polymetallic complex led to a dramatic reversal of the enantioselectivity and increased catalyst activity.

Key role of the Lewis base position in asymmetric bifunctional catalysis: design and evaluation of a new ligand for chiral polymetallic catalysts. Publishing Authors By Initials

I Fujimori,T Mita,K Maki,M Shiro,A Sato,S Furusho,M Kanai,M Shibasaki,

For similar natural sciences: chemistry: chemistry, organic: isomerism: stereoisomerism research abstracts see: natural sciences: chemistry: chemistry, organic: isomerism: stereoisomerism research

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Key role of the Lewis base position in asymmetric bifunctional catalysis: design and evaluation of a new ligand for chiral polymetallic catalysts. Journal Published:

PUBLICATION TYPE: Research Support, Non-U.S. Gov

Journal: Journal of the American Chemical Society

VOLUME: 128

Page Numbers: 16438-9

Journal Abbreviation: J. Am. Chem. Soc.

ISSN: 0002-7863

DAY: 27

MONTH: Dec

YEAR: 2006

Key role of the Lewis base position in asymmetric bifunctional catalysis: design and evaluation of a new ligand for chiral polymetallic catalysts. Information

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LANGUAGE: eng

NlmUniqueID: 7503056

Key role of the Lewis base position in asymmetric bifunctional catalysis: design and evaluation of a new ligand for chiral polymetallic catalysts. Keywords Mesh Terms:

KEYWORDS: Stereoisomerism

MESH TERMS: chemistry

Chemical & Substance for Abstract: Key role of the Lewis base position in asymmetric bifunctional catalysis: design and evaluation of a new ligand for chiral polymetallic catalysts. Information

Substance Name: Phosphines

Registry Number: 0

Grant and Affiliation Information for Key role of the Lewis base position in asymmetric bifunctional catalysis: design and evaluation of a new ligand for chiral polymetallic catalysts.

AFFILIATION: Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan.

Country: United States

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MEDLINETA: J Am Chem Soc

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