Catalytic Asymmetric Cyclopropanation of Enones with Dimethyloxosulfonium Methylide Promoted by a La−Li<sub>3</sub>−(Biphenyldiolate)<sub>3</sub> + NaI Complex

Kakei, Hiroyuki; Sone, Takanori; Sohtome, Yoshihiro; Matsunaga, Shigeki; Shibasaki, Masakatsu

doi:10.1021/ja076797c

Cited by 112 publications

(50 citation statements)

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“…The molecular structure of 3 is quite similar to that of analogous La complex [36], in which the central Nd ion is bound to three chelating asymmetric guanidinates and coordinated to one THF molecule in a capped octahedron. The average Nd-N bond distance of 2.492(6) Å is in the range for the published analogues [7] and the C-N distances within the chelate rings (av. 1.345(5) Å) are consistent with partial double bond character.…”

Section: Introductionmentioning

confidence: 81%

“…For example, the heterobimetallic binaphthoxide and phenoxide complexes of lanthanide and alkali metals have been explored to be versatile asymmetric catalysts in organic syntheses [1][2][3][4][5][6][7][8][9]. Various organometallic complexes of trivalent lanthanide and alkali metals [10][11][12][13][14][15][16][17], as well as the complexes of divalent lanthanide and sodium metals [18,19] have proven to be more effective catalysts in polymerization of nonpolar and polar monomers than their corresponding lanthanide complexes without alkali metals.…”

Section: Introductionmentioning

confidence: 99%

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Heterobimetallic complexes of lanthanide and lithium metals with dianionic guanidinate ligands: Syntheses, structures and catalytic activity for amidation of aldehydes with amines

Qian

Zhang

et al. 2010

Journal of Organometallic Chemistry

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Section: Introductionmentioning

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Heterobimetallic complexes of lanthanide and lithium metals with dianionic guanidinate ligands: Syntheses, structures and catalytic activity for amidation of aldehydes with amines

Qian

Zhang

et al. 2010

Journal of Organometallic Chemistry

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“…For the Corey-Chaykovsky cyclopropanation of enones and an R, -unsaturated N-acylpyrrole 13 as an ester surrogate, biphenyldiol 1-H 2 gave better enantioselectivity than BINOL (Scheme 3). 14,15 In cyclopropanation, a NaI additive also played a key role to improve enantioselectivity. Electrospray ionization mass spectrometry (ESI-MS) analysis, as well as control experiments, indicated that a partial alkali metal exchange occurred in situ to afford a La-Li 2 -Na-tris(biphenoxide 1) complex as the most reactive and enantioselective active species (Scheme 3).…”

Section: New Development In Remb Catalystsmentioning

confidence: 99%

“…Tamiflu (14) 26 is thought to be effective for protecting human beings against a possible influenza pandemic. Developing a truly efficient synthetic route by which Tamiflu can be produced in sufficient amounts to satisfy a worldwide demand is an ongoing project in our group.…”

Section: Catalytic Asymmetric Synthesis Of Tamiflumentioning

confidence: 99%

Recent Progress in Asymmetric Bifunctional Catalysis Using Multimetallic Systems

et al. 2009

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The concept of bifunctional catalysis, wherein both partners of a bimolecular reaction are simultaneously activated, is very powerful for designing efficient asymmetric catalysts. Catalytic asymmetric processes are indispensable for producing enantiomerically enriched compounds in modern organic synthesis, providing more economical and environmentally benign results than methods requiring stoichiometric amounts of chiral reagents. Extensive efforts in this field have produced many asymmetric catalysts, and now a number of reactions can be rendered asymmetric. We have focused on the development of asymmetric catalysts that exhibit high activity, selectivity, and broad substrate generality under mild reaction conditions. Asymmetric catalysts based on the concept of bifunctional catalysis have emerged as a particularly effective class, enabling simultaneous activation of multiple reaction components. Compared with conventional catalysts, bifunctional catalysts generally exhibit enhanced catalytic activity and higher levels of stereodifferentiation under milder reaction conditions, attracting much attention as next-generation catalysts for prospective practical applications. In this Account, we describe recent advances in enantioselective catalysis with bifunctional catalysts. Since our identification of heterobimetallic rare earth-alkali metal-BINOL (REMB) complexes, we have developed various types of bifunctional multimetallic catalysts. The REMB catalytic system is effective for catalytic asymmetric Corey-Chaykovsky epoxidation and cyclopropanation. A dinucleating Schiff base has emerged as a suitable multidentate ligand for bimetallic catalysts, promoting catalytic syn-selective nitro-Mannich, anti-selective nitroaldol, and Mannich-type reactions. The sugar-based ligand GluCAPO provides a suitable platform for polymetallic catalysts; structural elucidation revealed that their higher order polymetallic structures are a determining factor for their function in the catalytic asymmetric Strecker reaction. Rational design identified a related ligand, FujiCAPO, which exhibits superior performance in catalytic asymmetric conjugate addition of cyanide to enones and a catalytic asymmetric Diels-Alder-type reaction. The combination of an amide-based ligand with a rare earth metal constitutes a unique catalytic system: the ligand-metal association is in equilibrium because of structural flexibility. These catalytic systems are effective for asymmetric amination of highly coordinative substrate as well as for Mannich-type reaction of alpha-cyanoketones, in which hydrogen bonding cooperatively contributes to substrate activation and stereodifferentiation. Most of the reactions described here generate stereogenic tetrasubstituted carbons or quaternary carbons, noteworthy accomplishments even with modern synthetic methods. Several reactions have been incorporated into the asymmetric synthesis of therapeutics (or their candidate molecules) such as Tamiflu, AS-3201 (ranirestat), GRL-06579A, and ritodrine, illustrating the usefuln...

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“…Based on the importance of the cyclopropane unit, and the pioneering investigations of Aggarwal and Gaunt, Matsunaga, Shibasaki and coworkers began to investigate the possible use of rare-earth metals for the asymmetric cyclopropanation of enones and α,β-unsaturated acylpyrroles [33]. In addition, their previous development of catalytic enantioselective epoxidation reactions of the same substrates supported the suggestion that a domino Michael/intramolecular substitution mechanism would be applicable to asymmetric reactions with stabilized ylides.…”

Section: Miscellaneousmentioning

confidence: 99%

Asymmetric Bifunctional Catalysis Using Heterobimetallic and Multimetallic Systems in Enantioselective Conjugate Additions

Córdova

2010

Catalytic Asymmetric Conjugate Reactions

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The conjugate addition of a nucleophile to an α,β-unsaturated carbonyl compound (commonly referred to as Michael addition) is a classic carbon-carbon bond-forming reaction in organic synthesis [1]. It is also an important transformation for the formation of carbon-heteroatom bonds. As these reactions often result in the creation of a stereogenic center, the importance of controlling the stereoselectivity of such conjugate addition reactions has sparked intense and impressive developments by chemists in both academia and industry. The use of stoichiometric amounts of chiral reagents, ligands, and auxiliaries has led to the development of several asymmetric Michael reactions [2]. However, the need to develop more effective and atom-economic methods has led to the utilization of asymmetric catalysis in enantioselective conjugate additions (ECAs) [3]. In Nature, natural catalysts -enzymes -mainly use general base and acid catalysis to achieve carbon-carbon bond-forming reactions, with almost exclusive stereocontrol [4]. This is accomplished in the active site of the enzyme by the perfect arrangement and dual activation of the electrophilic acceptor and nucleophilic donor substrate. Sometimes, a metallic cofactor in cooperation with the neighboring amino acids of the active site is necessary to achieve C−C bond-formation. In this context, type II aldolase enzymes employ a Zn ion (which is a Lewis acid) to activate dihydroxyacetone phosphate, in cooperation with an amino acid residue (which acts as a Brønsted base) to generate, regioselectively, an enolate (Figure 4.1a) [4]. At the same time, the electrophilic aldehyde acceptor is a Brønsted acid activated by an amino acid residue, such that stereoselective C−C bond-formation will occur with excellent enantioselectivity. In Nature, millions of years of evolution were required order to achieve this perfectly orchestrated transformation in an aqueous medium. Consequently, in taking their inspiration from Nature, research chemists have developed asymmetric catalysts that may reach impressive levels of enantioselectivity in carbon-carbon bond-forming reactions [5]. One way to achieve such enantioselectivity is to employ a strategy similar to that utilized by type II aldolase enzymes, which includes asymmetric bifunctional catalysis and metal activation (Figure 4.1b) Catalytic Asymmetric Conjugate Reactions. Edited by Armando Córdova

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Catalytic Asymmetric Cyclopropanation of Enones with Dimethyloxosulfonium Methylide Promoted by a La−Li₃−(Biphenyldiolate)₃ + NaI Complex

Cited by 112 publications

References 14 publications

Heterobimetallic complexes of lanthanide and lithium metals with dianionic guanidinate ligands: Syntheses, structures and catalytic activity for amidation of aldehydes with amines

Heterobimetallic complexes of lanthanide and lithium metals with dianionic guanidinate ligands: Syntheses, structures and catalytic activity for amidation of aldehydes with amines

Recent Progress in Asymmetric Bifunctional Catalysis Using Multimetallic Systems

Asymmetric Bifunctional Catalysis Using Heterobimetallic and Multimetallic Systems in Enantioselective Conjugate Additions

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Catalytic Asymmetric Cyclopropanation of Enones with Dimethyloxosulfonium Methylide Promoted by a La−Li3−(Biphenyldiolate)3 + NaI Complex

Cited by 112 publications

References 14 publications

Heterobimetallic complexes of lanthanide and lithium metals with dianionic guanidinate ligands: Syntheses, structures and catalytic activity for amidation of aldehydes with amines

Heterobimetallic complexes of lanthanide and lithium metals with dianionic guanidinate ligands: Syntheses, structures and catalytic activity for amidation of aldehydes with amines

Recent Progress in Asymmetric Bifunctional Catalysis Using Multimetallic Systems

Asymmetric Bifunctional Catalysis Using Heterobimetallic and Multimetallic Systems in Enantioselective Conjugate Additions

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Catalytic Asymmetric Cyclopropanation of Enones with Dimethyloxosulfonium Methylide Promoted by a La−Li₃−(Biphenyldiolate)₃ + NaI Complex