(1R,2S)-(+)-cis-1-Amino-2-indanol:  An Effective Ligand for Asymmetric Catalysis of Transfer Hydrogenations of Ketones

Palmer, Matthew J.; Walsgrove, Tim; Wills, Martin

doi:10.1021/jo970405a

Cited by 169 publications

(72 citation statements)

References 39 publications

(19 reference statements)

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“…S2; square brackets represent other coordinations and bonds to the metal) formed from reaction of specific species will be referred to using the m∕z value of the most intense peak of the isotope distribution. Although these intermediates are predicted, their high reactivity and short lifetimes prevented isolation and detection (5,11,15) prior to this study.…”

Section: Resultsmentioning

confidence: 99%

“…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.…”

mentioning

confidence: 99%

“…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%

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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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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

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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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“…Reduction of 1-indanone 9 proceeded smoothly to give (R)-2,3-dihydro-1H-inden-1-ol 16 in high enantioselectivity (ee 95%, entry 6) 16 and reduction of α-tetralone 10 produced the corresponding (R)-alcohol 17 with the best enantioselectivity (96%) (entry 7). 17 In order to determine the minimum amount of reagent required to obtain the maximum selectivity, the reduction of α-tetralone 10 was performed with varying amounts (2, 5, 7 and 10 mol %) of chiral 2-methyl-1,3,2-dioxaborolane catalyst 3 ( Table 2). …”

Section: Resultsmentioning

confidence: 99%

Enantioselective reduction of prochiral aryl ketones using a novel chiral auxiliary derived from a labdane diterpene

Cifuente¹,

Tonn²

2011

Arkivoc

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A novel chiral 2-methoxy-1,3,2-dioxaborolane derived from 2α,3α-dihydroxycativic acid, a labdane-type diterpene isolated from aerial parts of Baccharis scandens DC., is reported as a highly effective chiral auxiliary. This compound has been successfully used in the borane dimethyl sulfide complex-mediated asymmetric reduction of prochiral aryl ketones at room temperature. Very good chemical yields (up to 89%) and high enantioselectivities were obtained.

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“…This reaction, for which there is a considerable amount of experimental data available [8,9], is well suited for probing the capabilities of new ligands, and the products themselves are important in organic synthesis. With our new bicyclic ligands readily available and in the light of the new findings by Noyori [10] that amino alcohols accelerate ruthenium-catalyzed transfer hydrogenations, we realized the potential of our ligands in this reaction.…”

Section: Ruthenium-catalyzed Transfer Hydrogenation Of Ketonesmentioning

confidence: 99%

Development of a new methodology for the preparation of optically active alcohols

Andersson

2004

Pure and Applied Chemistry

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This article summarizes our recent achievements in the asymmetric catalytic formation of chiral alcohols using 3-substituted, 2-azanorbornyl-based ligands. The use of this structural unit in ligand synthesis offers several advantages over the analogous proline chemistry, such as equal availability of both enantiomers and increased rigidity of the catalysts. This ligand has been found to be very useful for the two reactions described in this paper: the ruthenium-catalyzed transfer hydrogenation of ketones, and the base-mediated rearrangement of epoxides.

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(1R,2S)-(+)-cis-1-Amino-2-indanol: An Effective Ligand for Asymmetric Catalysis of Transfer Hydrogenations of Ketones

Cited by 169 publications

References 39 publications

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

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

Enantioselective reduction of prochiral aryl ketones using a novel chiral auxiliary derived from a labdane diterpene

Development of a new methodology for the preparation of optically active alcohols

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