The First Heterobimetallic Multifunctional Asymmetric Catalyst

Sasai, Hiroaki; Arai, Takayoshi; Satow, Y.; Houk, K. N.; Shibasaki, Masakatsu

doi:10.1021/ja00128a005

Cited by 308 publications

(157 citation statements)

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“…However, the reaction conditions are strongly basic and therefore often lead to the above-mentioned disadvantages. [4] The use of a neutral transition metal catalyst has been investigated with varying degrees of success by a number of groups in the past few years: Brunner et al introduced Co-(acac) 2 together with an optically active diamine, [5] Desimoni et al reported on chiral copper catalysts derived from natural α-amino acids, [6] and Pfaltz et al presented chiral tetradentate oxazolines as ligands for Co II -catalyzed asymmetric Michael reactions. [7] All these methods, however, suffer either from the need for anhydrous reaction conditions, low reaction temperatures or low yields.…”

Section: Introductionmentioning

confidence: 99%

“…We are searching for an alternative to ShibasakiЈs bimetallic catalysis of the Michael reaction, [4] which avoids basic reaction conditions, and we have already reported on this subject several times. [8] It is our strategy to screen a large number of metal complexes, generated in situ by the combination of many ligands with metal salts, for their activity and selectivity.…”

Section: Introductionmentioning

confidence: 99%

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Construction of Quaternary Stereocenters by Nickel-Catalysis of Asymmetric Michael Reactions

Christoffers¹,

Rößler

Werner

2000

Eur. J. Org. Chem.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Construction of Quaternary Stereocenters by Nickel-Catalysis of Asymmetric Michael Reactions

Christoffers¹,

Rößler

Werner

2000

Eur. J. Org. Chem.

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“…Isolation of the dimer 4 indicates that added water can react with this important class of bifunctional catalyst to give new products.…”

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confidence: 99%

Characterization of Dimeric and Tetrameric μ‐Hydroxide Ytterbium(III) Binaphtholate Complexes

et al. 2007

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This manuscript is dedicated to Prof. M. Shibasaki, whose creativity and insight has changed the way we think of asymmetric Lewis acid catalysis.Supporting information for this article is available on the WWW under http://asc.wiley-vch.de/home/.Abstract: Shibasakis heterobimetallic Lewis acids,Ln (M = Li, Na, K and Ln = lanthanide), are an exceptionally useful class of asymmetric catalysts that exhibit high levels of enantioselectivity across a wide range of reactions. In many instances, it is necessary to add water (and base) to achieve maximum enantioselectivity. We have investigated the reaction of water withand observed formation of a novel hydroxide-bridged dimer (M = Li) and tetramer (M = K). These compounds have been characterized, including Xray structure analysis. Under anhydrous conditions, only 6-coordinate monomericYb complexes were isolated and characterized by Xray crystallography. Isolation of the dimer 4 indicates that added water can react with this important class of bifunctional catalyst to give new products. C H T U N G T R E N N U N G (m-OH) 2 and tetramer K 4 A C H T U N G T R E N N U N G (THF) 9 A C H T U N G T R E N N U N G (BINOLate) 6 Yb 4 A C H T U N G T R E N N U N G (m 3 -OH)Keywords: additives; asymmetric catalysis; bridging hydroxide; heterobimetallic catalysts; lanthanides; Lewis acidsIn the early 1990s, Shibasaki and co-workers reported the synthesis and applications of a series of heterobimetallic Lewis acid catalysts, Figure 1, M = Li, Na, K and Ln = lanthanideA C H T U N G T R E N N U N G (III)] and their 7-coordinate hydrates[1-6] These bifunctional catalysts are exceptional in their ability to catalyze a broad range of asymmetric transformations, such as the Henry reaction, [1,7] conjugate additions, [4,5,[7][8][9][10] aldol condensations, [6,11] cyanoethoxycarbonylation of aldehydes, [12] and hydrophosphonylation of aldehydes and cyclic imines, [13,14] to name a few. Despite the widespread successful application of these heterobimetallic catalysts in asymmetric synthesis, their reaction mechanisms are not well understood, because their multifunctional nature complicates mechanistic studies.

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“…Extensive studies showed [47][48][49] that the lanthanum-sodium-BINOL complex (LSB) (47a) is very selective in the addition of prochiral β-keto esters to methyl vinyl ketone (eqn. 43 & 44 + (46) up to 80% ee…”

Section: Figurementioning

confidence: 99%

Catalytic, enatioselective Michael addition reactions

Jha¹,

Joshi²

2002

Arkivoc

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This review summarizes the tremendous achievements in the field of catalytic enantioselective Michael addition reaction involving the attack of soft nucleophiles on α,β-unsaturated systems. The reaction has evolved during past two decades, from stoichiometric to catalytic. A large number of efficient catalytic systems have been used to generate chiral Michael adducts in high optical purity. Several chiral alkaloids were used for the enantioselective addition of thiols and dialkylmalonates to cyclic and linear enones to give product in moderate to high enantioselectivity. Chiral crown ethers in conjugation with metal alkoxides were found to be the catalyst of choice for the addition of substituted α-phenylesters to linear enones. Proline derived catalysts gave product in moderate in moderate to high enantioselectivity where NO 2 group was present as an activator in either Michael donor or acceptor. BINAP based catalysts were found to be superior in Michael addition of α-nitrile substituted esters to linear enones. A new class of heterobimetallic catalysts based on BINOL ligand was found to be highly versatile for an array of Michael donors and acceptors to provide products in very high optical purity. Metal complexes based on chiral N,N-dioxides were found to be superior for the addition of arylthiols to both linear and cyclic enones to have product in high enantiomeric excess.

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The First Heterobimetallic Multifunctional Asymmetric Catalyst

Cited by 308 publications

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Construction of Quaternary Stereocenters by Nickel-Catalysis of Asymmetric Michael Reactions

Construction of Quaternary Stereocenters by Nickel-Catalysis of Asymmetric Michael Reactions

Characterization of Dimeric and Tetrameric μ‐Hydroxide Ytterbium(III) Binaphtholate Complexes

Catalytic, enatioselective Michael addition reactions

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