Linked-BINOL: An Approach towards Practical Asymmetric Multifunctional Catalysis

Matsunaga, Shigeki; Ohshima, Takashi; Shibasaki, Masakatsu

doi:10.1002/1615-4169(200201)344:1<3::aid-adsc3>3.0.co;2-2

Cited by 116 publications

(11 citation statements)

References 24 publications

(40 reference statements)

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“…Binol is an important chiral building block and has been widely used in asymmetric catalysis,17, 18 and for enantioselective fluorescence sensors bearing a variety of recognition elements 19–30. In early work, a binol‐based bisboronic acid ( 1) was used to recognize the enantiomers of monosaccharides, such as D / L ‐glucose, ‐fructose, and ‐galactose 2.…”

Section: Logarithm Of 1:1 Stability Constants K Fluorescence Enhancementioning

confidence: 99%

Investigating the effect of temperature on depth profiles of biological material using ToF‐SIMS

Piwowar

Fletcher

Lockyer

et al. 2011

Surface & Interface Analysis

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In this study we examine the depth profiles of two bio-materials, an amino acid (arginine) and a polypeptide (Gly-Gly-Tyr-Arg), to observe the effects of temperature on sample analysis with time of flight secondary ion mass spectrometry (ToF-SIMS). The samples were prepared as dried droplet films on silicon and were analyzed at room temperature (300 K) and at cryogenic temperatures (100 K). Under cryogenic analysis conditions, molecular ion yields at the steady state increased by factors of 1.8 and 5 for arginine and the tetrapeptide respectively compared to analysis at room temperature. Increases are also observed in arginine dimer and trimer ion formation by factors of 6 and 5 respectively, while the lower mass fragment ions investigated did not change in intensity by more than 30%. Further analysis of the results show that the decrease in the steady state ion yield with primary ion fluence at 300 K is reduced when analyzed at 100 K, indicating a decrease in chemical damage. These results suggest that analysis under cryogenic conditions provides several benefits for the analysis of biological compounds and hence for 3D molecular imaging of cells and tissue.

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Section: Logarithm Of 1:1 Stability Constants K Fluorescence Enhancementioning

confidence: 99%

Investigating the effect of temperature on depth profiles of biological material using ToF‐SIMS

Piwowar

Fletcher

Lockyer

et al. 2011

Surface & Interface Analysis

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“…Linked-BINOL ligands such as compound 13 were developed by Shibasaki and co-workers in order to provide a new generation of heterobimetallic multifunctional chiral catalysts with enhanced kinetic stability. 19 As a beneficial side effect, the linking of two BINOL moieties facilitates recovery and reuse of these chiral ligands. Dinuclear zinc complexes of linked-BINOL ligands turned out to be extraordinarily efficient catalysts for direct aldol reactions.…”

Section: Zinc-linked-binol Complexesmentioning

confidence: 99%

Recent Advances in Metal-Catalyzed Asymmetric Conjugate Additions

Christoffers¹,

Koripelly²,

Rosiak³

et al. 2007

Synthesis

438

104

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The conjugate addition of carbon nucleophiles to acceptor activated olefins is one of the most important reactions for carbon-carbon bond formation. With optically active metal complexes this transformation can be catalyzed enantioselectively. This review is a collection of the newer literature (since 2001) on this topic. The metal salts and complexes applied are in a broad range, starting from solely Lewis acidic M(II) and M(III) compounds, such as magnesium, zinc, boron, aluminum and the lanthanoids. Transitionmetal catalysts suitable for asymmetric conjugate additions are compounds of ruthenium, iridium, nickel, and palladium. The most flourishing fields are, however, the catalysis with rhodium and copper complexes. Rhodium catalysts often have a chiral diphosphane like BINAP, or an optically active olefin as the ligand, the latter being a newer development. The privileged ligand structures for copper catalysts are monodentate phosphoramidites with axially chiral BINOL or other biphenol units.

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“…Generally, the Michael reaction of dialkyl malonates does not proceed easily under traditional Lewis acid catalyzed conditions,21d but some base catalysts such as sodium ethoxide show high catalytic activity toward these substrates 21c. Shibasaki et al recently reported that the La‐linked‐BINOL catalysts were highly efficient for the asymmetric Michael reaction of dialkyl malonates with enones, in which the metal center and the naphthoxide moiety act as a Lewis acid and Brønsted base, respectively 26. In a similar fashion, the Michael reaction by the Cu 2+ ‐mont likely proceeds by bifunctional catalysis between the Lewis acid Cu complex and the silicate layer of the mont; the latter efficiently abstracts a proton from 1,3‐dicarbonyl compounds.…”

Section: Resultsmentioning

confidence: 99%

Monomeric Metal Aqua Complexes in the Interlayer Space of Montmorillonites as Strong Lewis Acid Catalysts for Heterogeneous Carbon–Carbon Bond‐Forming Reactions

Kawabata

Kato

Mizugaki

et al. 2004

Chemistry A European J

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Montmorillonite-enwrapped copper and scandium catalysts (Cu(2+)- and Sc(3+)-monts) were easily prepared by treating Na(+)-mont with the aqueous solution of the copper nitrate and scandium triflate, respectively. The resulting Cu(2+)- and Sc(3+)-monts showed outstanding catalytic activities for a variety of carbon-carbon bond-forming reactions, such as the Michael reaction, the Sakurai-Hosomi allylation, and the Diels-Alder reaction, under solvent-free or aqueous conditions. The remarkable activity of the mont catalysts is attributable to the negatively charged silicate layers that are capable of stabilizing metal cations. Furthermore, these catalysts were reusable without any appreciable loss in activity and selectivity. The Cu(2+)-mont-catalyzed Michael reaction proceeds via a ternary complex in which both the 1,3-dicarbonyl compound and the enone are coordinated to a Lewis acid Cu(2+) center.

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Linked-BINOL: An Approach towards Practical Asymmetric Multifunctional Catalysis

Cited by 116 publications

References 24 publications

Investigating the effect of temperature on depth profiles of biological material using ToF‐SIMS

Investigating the effect of temperature on depth profiles of biological material using ToF‐SIMS

Recent Advances in Metal-Catalyzed Asymmetric Conjugate Additions

Monomeric Metal Aqua Complexes in the Interlayer Space of Montmorillonites as Strong Lewis Acid Catalysts for Heterogeneous Carbon–Carbon Bond‐Forming Reactions

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