Ligand Design for Catalytic Asymmetric Reduction

Ohkuma, Takeshi; Kitamura, Masato; Noyori, Ryoji

doi:10.1002/9780470098004.ch1

Cited by 32 publications

(33 citation statements)

References 102 publications

(133 reference statements)

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“…Such ligands are considered as privileged for the reduction of activated ketonic substrates. A overwhelming amount of literature has been written on the subject, including several excellent book chapters [1,2] . This, coupled with the commercial availability of several classes of diphosphines and catalyst precursors, offers an excellent starting point for applied catalysis.…”

Section: Asymmetric Hydrogenation Of Activated Ketones and B -Keto Esmentioning

confidence: 99%

Carbonyl Hydrogenation

Hedberg

2008

Modern Reduction Methods

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Section: Asymmetric Hydrogenation Of Activated Ketones and B -Keto Esmentioning

confidence: 99%

Carbonyl Hydrogenation

Hedberg

2008

Modern Reduction Methods

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“…Enantiomerically pure alcohols play a significant role in the pharmaceutical and agrochemical industries. 1,2 In this respect, the most effective and efficient class of catalysts for the enantioselective hydrogenation of pro-chiral ketones to chiral alcohols is the Ru II diphosphine diamine type of complexes developed by Noyori and co-workers. 3,4 In these catalysts, the active species is the trans-dihydride Ru complex, which is formed by the reaction of the precursor dichloro complex with dihydrogen and alkoxide bases.…”

Section: Introductionmentioning

confidence: 99%

trans-FeII(H)2(diphosphine)(diamine) complexes as alternative catalysts for the asymmetric hydrogenation of ketones? A DFT study

et al. 2011

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New insights into the structural, electronic and catalytic properties of Fe complexes are provided by a density functional theory study of model as well as real [Fe(II)(H)(2)(diphosphine)(diamine)] systems. Calculations conducted using several different functionals on the trans- and cis-isomers of [Fe(II)(H)(2)(S-xylbinap)(S,S-dpen)] complexes show that, as with the [Ru(II)(H)(2)(diphosphine)(diamine)] complexes, the trans-[Fe(II)(H)(2)(diphosphine)(diamine)] complex is the more stable isomer. Analysis of the spin states of the trans-[Fe(II)(H)(2)(diphosphine)(diamine)] complexes also shows that the singlet state is significantly more stable than the triplet and the quintet, as with the [Ru(II)(H)(2)(diphosphine)(diamine)] complexes. Calculations of the catalytic cycle for the hydrogenation of ketones using two model trans-[M(II)(H)(2)(PH(3))(2)(en)] catalysts, where M = Ru and Fe, show that the mechanism of reaction as well as the activation energies are very similar, in particular: (i) the ketone/alcohol hydrogen transfer reaction occurs through the metal-ligand bifunctional mechanism, with energy barriers of 3.4 and 3.2 kcal mol(-1) for the Ru- and Fe-catalysed reactions, respectively; (ii) the heterolytic splitting of H(2) across the M[partial double bond, bottom dashed]N bond for the regeneration of the Ru and Fe catalysts has an activation barrier of 13.8 and 12.8 kcal mol(-1), respectively, and is expected to be the rate determining step for both catalytic systems. The reduction of acetophenone by trans-[M(II)(H)(2)(S-xylbinap)(S,S-dpen)] complexes along two competitive reaction pathways, shows that the intermediates for the Fe catalytic system are similar to those responsible for the high enantioselectivity of (R)-alcohol in those proposed trans-[Ru(II)(H)(2)(S-xylbinap)(S,S-dpen)] catalysed acetophenone hydrogenation reaction. Thus the high enantiomeric excess in the hydrogenation of acetophenone could, in principle, be achieved using Fe catalysts.

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“…For example, chiral alkylamine–alcohol catalysts 5 and 6 (Figure a) can efficiently promote the addition of zinc reagents to aldehydes to give the corresponding chiral products with good to high enantioselectivities . We then envisioned that either primary or secondary alkylamines could be utilized as raw materials to assemble the target biaryl alkylamine–alcohols via catalytic reductive amination (Figure b). In this scenario, two major challenges might be encountered: (1) the unpredictable reactivity of reductive amination, as there are not enough data to guarantee the success of the use of alkylamines as nucleophiles; (2) successful examples of the atropoenantioselective construction of axially chiral biaryls are still in high demand.…”

mentioning

confidence: 99%

Ruthenium-Catalyzed Atropoenantioselective Synthesis of Axial Biaryls via Reductive Amination and Dynamic Kinetic Resolution

Guo

Zhang

et al. 2018

Org. Lett.

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The unprecedented ruthenium-catalyzed atropoenantioselective reductive amination of aldehydes with alkylamines via a cascade transfer hydrogenation and dynamic kinetic resolution strategy is described. This protocol features broad substrate scope and good functional group tolerance and allows the rapid assembly of axially chiral biaryls in good to high yields with high to excellent enantioselectivities. In addition, such structural motifs may have potential applications in enantioselective catalysis as chiral ligands or catalysts.

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Ligand Design for Catalytic Asymmetric Reduction

Cited by 32 publications

References 102 publications

Carbonyl Hydrogenation

Carbonyl Hydrogenation

trans-FeII(H)2(diphosphine)(diamine) complexes as alternative catalysts for the asymmetric hydrogenation of ketones? A DFT study

Ruthenium-Catalyzed Atropoenantioselective Synthesis of Axial Biaryls via Reductive Amination and Dynamic Kinetic Resolution

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