Metal−Ligand Bifunctional Catalysis:  A Nonclassical Mechanism for Asymmetric Hydrogen Transfer between Alcohols and Carbonyl Compounds

Noyori, Ryoji; Yamakawa, and Masashi; Hashiguchi, Shohei

doi:10.1021/jo010721w

Cited by 846 publications

(484 citation statements)

References 74 publications

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“…69, 74 In passing, it is worth noting the resemblance between the 6-membered ring transition states discussed here and those associated with Noyori's transfer hydrogenation catalysts. 85 This also involve metal-ligand bifunctional cooperativity, 48,86 and calculations 87 have shown that transfer of the hydrogen from the alcohol to the catalyst occurs via a cyclic 6-membered transition state.…”

Section: Overview Of Heteroatom-assisted C-h Activationmentioning

confidence: 99%

Mechanisms of C–H bond activation: rich synergy between computation and experiment

et al. 2009

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Image reproduced with permission of Christophe CoperetPapers published in this issue include:A combined picture from theory and experiments on water oxidation, oxygen reduction and proton pumping Per E. M. Siegbahn and Margareta R. A. Blomberg, Dalton Trans., 2009, DOI: 10.1039 Recent computational studies of C-H bond activation at late transition metal systems are discussed and processes where lone pair assistance via heteroatom co-ligands or carboxylates are highlighted as a particularly promising means of cleaving C-H bonds. The term 'ambiphilic metal ligand activation' (AMLA) is introduced to describe such reactions.

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Section: Overview Of Heteroatom-assisted C-h Activationmentioning

confidence: 99%

Mechanisms of C–H bond activation: rich synergy between computation and experiment

et al. 2009

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“…1, 4 and Ru-H Fig. 1, 5 by a bifunctional transfer of a hydride and a proton effects the oxidation of alcohols and reduction of ketones (5,11,(15)(16)(17)(18)(19)(20).…”

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confidence: 99%

Transient Ru-methyl formate intermediates generated with bifunctional transfer hydrogenation catalysts

Perry

Brownell

Chingin

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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Desorption electrospray ionization (DESI) coupled to high-resolution Orbitrap mass spectrometry (MS) was used to study the reactivity of a (β-amino alcohol)(arene)RuCl transfer hydrogenation catalytic precursor in methanol (CH 3 OH). By placing ½ðp-cymeneÞ RuCl 2 2 on a surface and spraying a solution of β-amino alcohol in methanol, two unique transient intermediates having lifetimes in the submillisecond to millisecond range were detected. These intermediates were identified as Ru (II) and Ru (IV) complexes incorporating methyl formate (HCOOCH 3 ). The Ru (IV) intermediate is not observed when the DESI spray solution is sparged with Ar gas, indicating that O 2 dissolved in the solvent is necessary for oxidizing Ru (II) to Ru (IV). These proposed intermediates are supported by high-resolution and high mass accuracy measurements and by comparing experimental to calculated isotope profiles. Additionally, analyzing the bulk reaction mixture using gas chromatography-MS and nuclear magnetic resonance spectroscopy confirms the formation of HCOOCH 3 . These results represent an example that species generated from the (β-amino alcohol)(arene)RuCl (II) catalytic precursor can selectively oxidize CH 3 OH to HCOOCH 3 . This observation leads us to propose a pathway that can compete with the hydrogen transfer catalytic cycle. Although bifunctional hydrogen transfer with Ru catalysts has been well-studied, the ability of DESI to intercept intermediates formed in the first few milliseconds of a chemical reaction allowed identification of previously unrecognized intermediates and reaction pathways in this catalytic system. organometallic catalysis | reaction intermediates | ruthenium | kinetics C atalytic transfer hydrogenation (CTH) is an efficient method for the enantioselective reduction of multiple bonds (e.g., C═O and C═NR) in chemical and pharmaceutical syntheses (1-4). Typically, a hydrogen donor such as isopropanol is used as a convenient reducing agent and is oxidized to its corresponding ketone (5). As a catalytic version of the classical MeerweinPondorf-Verley reduction/Oppenaur oxidation (6-10), CTH provides a mild method for both ketone reduction and alcohol oxidation. Previous studies show that methanol (CH 3 OH) can serve as a hydrogen donor for (arene)Ru complexes ligated by β-amino alcohols (11), but the nature of the oxidized products from CH 3 OH has not been previously characterized (12). Additionally, some Pd and Ru (13, 14) catalysts can oxidize CH 3 OH to methyl formate (HCOOCH 3 ), but selective oxidation to methyl formate has not been observed previously for a transfer hydrogenation catalysis. Fig. 1 shows the mechanism proposed by Kenney, Heck, Walgrove, and Wills (15) for CTH when Fig. 1, 1 is treated with β-amino alcohol ligands in the presence of a base. Ligation of the cymene dimer Fig. 1, 1 with ligand Fig. 1, 2 generates the Ru-Cl catalyst precursor Fig. 1, 3, which undergoes dehydrohalogenation to form the Ru-amide Fig. 1, 4. An outer-sphere concerted hydrogen transfer of α-C─H to Ru and ─O─H t...

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“…Asymmetric hydrogenation is one of the most promising procedures for this purpose, and various efficient catalysts have been developed [27][28][29]. Transfer hydrogenolysis, catalyzed by similar complexes, are also effective for the enantioselective reduction of ketones to obtain the optically active alcohols [30][31][32]. Although sodium borohydride is commercially available, easily handled, and widely used in the laboratory and industry, the enantioselective borohydride reduction of ketones has not been developed [33][34][35].…”

Section: Enantioselective Borohydride Reductionmentioning

confidence: 99%

Manganese and cobalt 3-oxobutylideneaminato complexes: Design and application for enantioselective reactions

Yamada

Ikeno

Ohtsuka

et al. 2006

Science and Technology of Advanced Materials

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The optically active 3-oxobutylideneaminato transition-metal complexes have been developed as efficient catalysts for a variety of enantioselective reactions; e.g. the corresponding manganese(III) complexes catalyzed the enantioselective aerobic epoxidation of unfunctionalized olefins, and the corresponding cobalt complexes have been developed for the enantioselective borohydride reduction of various carbonyl compounds. The cobalt complexes could also be employed for the catalytic enantioselective cyclopropanation with diazoacetates and the Lewis acid catalyses such as the hetero Diels-Alder reaction, carbonyl-ene reaction, and 1,3-dipolar cycloaddition of nitrones. In the presence of the cobalt complex, the Henry reaction proceeded with a high enantioselectivity, and the enantioselective chemical fixation of carbon dioxide to obtain the optically active cyclic carbonate. In these Lewis acid catalyses, the valence of cobalt and the counter anion have significant effects on the reaction rate and stereoselectivity. q

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Metal−Ligand Bifunctional Catalysis: A Nonclassical Mechanism for Asymmetric Hydrogen Transfer between Alcohols and Carbonyl Compounds

Cited by 846 publications

References 74 publications

Mechanisms of C–H bond activation: rich synergy between computation and experiment

Mechanisms of C–H bond activation: rich synergy between computation and experiment

Transient Ru-methyl formate intermediates generated with bifunctional transfer hydrogenation catalysts

Manganese and cobalt 3-oxobutylideneaminato complexes: Design and application for enantioselective reactions

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