Homogeneous catalysis. A transition metal based catalyst for the Mukaiyama crossed-aldol reaction and catalyst deactivation by electron transfer.

Odenkirk, W.; Whelan, John; Bosnich, B.

doi:10.1016/0040-4039(92)89017-7

Cited by 41 publications

(18 citation statements)

References 14 publications

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“…Recently, organometallic compounds with a d 6 electron count have been used as Lewis-acid catalysts in C−C bond-forming reactions, e.g., in Diels−Alder and Mukaiyama reactions. − The prospective of using a chiral-at-metal piano-stool complex as a catalyst for such enantioselective transformations is very appealing, but it is imperative to ensure configurational stability of the catalyst, as racemization of the latter would have a dramatic effect on the enantiomeric excess of the resulting products.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Reactivity of Tethered η¹:η⁶-(Phosphinoarene)ruthenium Dichlorides

et al. 1998

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The coordination properties of ortho- and meta-substituted [(2-diphenylphosphanylethyl)phenyl]methanol 4a and 4b toward ruthenium(II) have been investigated. To ensure coordination of both the arene and the tethered phosphine, the labile ruthenium arene dimer [RuCl2(EtO2CC6H5)]2 (7) was synthesized and structurally characterized. Both the ortho and meta isomers [Ru(4a)Cl2] (9a) and [Ru(4b)Cl2] (9b) were characterized by X-ray crystallography. The lack of reactivity of the benzylic alcohol functionality in complexes 9a and 9b toward various P and C electrophiles is rationalized with extended Hückel calculations.

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Section: Introductionmentioning

confidence: 99%

Synthesis and Reactivity of Tethered η¹:η⁶-(Phosphinoarene)ruthenium Dichlorides

et al. 1998

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“…Schiff base ruthenium complexes have also been useful and were originally developed by Bosnich [62][63][64] for Mukaiyama and Sakurai reactions (Scheme 5). The presence of the strongly withdrawing nitrosyl group in the [Ru(salen)(NO)(H 2 O)] + monocation, 26, makes the metal site particularly acidic, as well as promoting lability of the ligand trans to it.…”

Section: Methodsmentioning

confidence: 99%

“…The side product formation could be circumvented by using higher catalyst loadings [62,64]. It is also possible that the side products (or even some, if not all, of the main product) could arise from secondary competing paths involving siliconium species generated in situ, such as those seen for related titanium-catalyzed processes [16,100].…”

Section: Mukaiyama Reactionmentioning

confidence: 99%

Lewis Acid Catalysis by Ruthenium Complexes

Faller¹,

Parr²

2006

COC

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Recent progress in the Lewis acid catalysis of organic reactions by ruthenium complexes. The review focuses on reactions in which coordinatively unsaturated ruthenium species function as conventional Lewis acids, rather than those involving oxidation or reduction, such as in hydrogenations. Particular emphasis is placed on the development of asymmetric catalysts. INTRODUCTIONLewis acid catalysis continues to be of major utility in organic synthesis [1]. Recent interest in asymmetric catalysis [2,3], particularly for the formation of carbon-carbon bonds, has spurred continuing developments in chiral Lewis acid catalysts [4][5][6]. Classically, Lewis acid catalysts would have involved: main group elements, such as boron or aluminum; tin or zinc; early transition metals, such as titanium; or some lanthanides. Koga developed one of the earliest successful main group catalysts [7]. Yamamoto has been a major contributor to the development of chiral main group Lewis acid catalysts [1,8]. Organometallic Lewis acids of late transition metals have been extensively studied by Beck [9], but the potential for stoichiometric asymmetric reactions on coordinated ligands was largely developed by others, particularly with rhenium [10,11] and molybdenum reagents [12]. These studies of stoichiometric reactions provided valuable information regarding mechanistic aspects and control of nucleophilic attack on coordinated substrates. The lack of sensitivity to decomposition from moisture is a particular advantage of the late transition metal Lewis acids and the potential for straightforward elaboration of the chirality at the metal center via ligand variation has allowed the development of effective asymmetric catalysts based on these metals. Lewis-acid catalysts based on ruthenium have been particularly effective and recent developments on this area will be covered here. Since the mechanisms of a large number of reactions catalyzed by ruthenium complexes involve loss of a ligand to provide a site for coordination of a substrate, a large fraction of the reactions could be viewed as involving Lewis acids. Thus this overview could cover much of the material in a recent monograph [13] which included 383 pages dedicated to ruthenium in organic synthesis. Nevertheless, we will primarily focus on reactions that have been traditionally viewed as catalyzed by Lewis acids and only provide a brief discussion of reactions in which one would expect the oxidation state of the ruthenium to change during the catalytic cycle. Another specific review and more general reviews are also recommended [13][14][15][16].

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“…The use of ruthenium compounds as a catalyst has proved to be effective method for the preparation of aldol adducts via a nonclassical aldol reaction. It is also noteworthy that the Mukaiyama aldol reaction even with a very low catalyst loading of ruthenium catalyst ([Ru(salen)NOH 2 O]SbF 6 ) gave the corresponding β-hydroxyketones in good yields (47). In 1995, Murahashi and co-workers found that low-valent hydridoruthenium phosphine complexes are effective catalysts for the activation of α-C-H bond of nitriles; therefore, they developed a novel aldol reaction of nitriles with carbonyl compounds to give α,β-unsaturated nitriles (48).…”

Section: Transition Metals Based Lewis Acidsmentioning

confidence: 99%

Aldol Reaction—Homogeneous

Cai

2011

Encyclopedia of Catalysis

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The aldol reaction is one of the oldest and important methods for the construction of carbon–carbon bonds in organic chemistry. Over the last 30 years, tremendous efforts have resulted in the development of many highly sophisticated and efficient catalytic methods of modern aldol reactions in catalytic chemo‐, regio‐, enantio‐, and diastereoselective manners. This review outlined those efforts in homogeneous catalysis and discussed with selected examples (331 publications) according to the different elemental types of catalysts, for example, transition metals and rare earth metals based Lewis acids, main group metals based catalysts, multifunctional catalysts, and metal‐free catalysts.

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Homogeneous catalysis. A transition metal based catalyst for the Mukaiyama crossed-aldol reaction and catalyst deactivation by electron transfer.

Cited by 41 publications

References 14 publications

Synthesis and Reactivity of Tethered η¹:η⁶-(Phosphinoarene)ruthenium Dichlorides

Synthesis and Reactivity of Tethered η¹:η⁶-(Phosphinoarene)ruthenium Dichlorides

Lewis Acid Catalysis by Ruthenium Complexes

Aldol Reaction—Homogeneous

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Homogeneous catalysis. A transition metal based catalyst for the Mukaiyama crossed-aldol reaction and catalyst deactivation by electron transfer.

Cited by 41 publications

References 14 publications

Synthesis and Reactivity of Tethered η1:η6-(Phosphinoarene)ruthenium Dichlorides

Synthesis and Reactivity of Tethered η1:η6-(Phosphinoarene)ruthenium Dichlorides

Lewis Acid Catalysis by Ruthenium Complexes

Aldol Reaction—Homogeneous

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Synthesis and Reactivity of Tethered η¹:η⁶-(Phosphinoarene)ruthenium Dichlorides

Synthesis and Reactivity of Tethered η¹:η⁶-(Phosphinoarene)ruthenium Dichlorides