An Additional Coordination Group Leads to Extremely Efficient Chiral Iridium Catalysts for Asymmetric Hydrogenation of Ketones

Xie, Jian‐Hua; Liu, Xiaoyan; Xie, Jian‐Bo; Wang, Lixin; Zhou, Qi‐Lin

doi:10.1002/anie.201102710

Cited by 221 publications

(126 citation statements)

References 36 publications

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“…[5][6][7][8][9][10] Of these, the family of [RuCl2(diphosphine)(diamine)] molecules developed by Noyori, Ikariya, Ohkuma and coworkers stands out. [11][12][13][14] Efficient enantioselective catalysts based on rhodium, [15][16][17] iridium, [18][19][20][21][22][23][24][25][26] and iron [27][28][29][30][31][32][33][34][35][36] have also been reported in the literature. Interest in iridium as a catalytic metal is sparked by the observation that it outperforms rhodium for the ionic hydrogenation of particularly difficult substrates such as imines and industrial processes based on Ir-catalyzed ketone hydrogenation have been implemented.…”

Section: Introductionmentioning

confidence: 99%

Ketone Hydrogenation with Iridium Complexes with “non N–H” Ligands: The Key Role of the Strong Base

et al. 2015

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Section: Introductionmentioning

confidence: 99%

Ketone Hydrogenation with Iridium Complexes with “non N–H” Ligands: The Key Role of the Strong Base

et al. 2015

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“…Another issue concerning the transition metal catalysis is the prevention of the formation of inactive dimers or trimers of the metal catalysts under the reaction condition, which is another important issue to improve the efficiency of transition metal catalysis. Traditional methods include the use of additives [62], or the immobilization of catalysts, the use of a bulky counteranion, and the introduction of a bulky or rigid ligand [63] to prevent catalyst dimerization. However, the development of strategy in ligand design to overcome this challenge and make chiral metal catalysis more powerful is still very much in demand.…”

Section: Solutionsmentioning

confidence: 99%

Toward Ideal Asymmetric Catalysis

Zhou¹,

Yu²

2014

Multicatalyst System in Asymmetric Catalysis

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“…[11] These Ir/SpiroPAP catalysts are likely to have a "metal-ligand bifunctional catalysis" mechanism, similar to the [RuCl 2 (diphosphine)(diamine)] catalysts. [12] The aromatic N À H of the Ir/SpiroPAP catalysts is more acidic than the aliphatic NÀH of [RuCl 2 (diphosphine)(diamine)] catalysts (the proton resonances of the NH or NH 2 group of the catalysts are as follows:…”

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confidence: 98%

Chiral Iridium Catalysts Bearing Spiro Pyridine‐Aminophosphine Ligands Enable Highly Efficient Asymmetric Hydrogenation of β‐Aryl β‐Ketoesters

et al. 2011

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Dedicated to Professor Christian Bruneau on the occasion of his 60th birthdayOptically active b-hydroxy acids and their derivatives are versatile chiral building blocks for many useful molecules, including pharmaceuticals and natural products.[1] Catalytic asymmetric hydrogenation of b-ketoesters is an efficient and economically feasible method for preparing these important chiral compounds. Pioneered by Noyori and co-workers, [2] the chiral ruthenium diphosphine complexes [RuX 2 -(diphosphine)] (X = Cl or Br) and their analogues have become by far the most popular catalysts for this transformation.[3] Many of them show excellent enantioselectivity [> 99 % enantiomeric excess (ee)] and extraordinarily high activity (turnover number (TON) of up to 100 000) for the hydrogenation of b-alkyl b-ketoesters.[4] However, only a few of these complexes exhibit high enantioselectivity for the hydrogenation of b-aryl b-ketoesters. Zhang et al. reported that the ruthenium catalysts bearing the ligands xylyl-obinapo [5] (3,3'-bis(3,5-dimethylphenyl)-2,2'-bis(diphenylphosphinoxy)-1,1'-binaphthyl) and C 3 *-TunePhos [6] give up to 99 % ee for the hydrogenation of b-aryl b-ketoesters. Using ruthenium complexes of 4,4'-substituted binap ligands (binap = 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl), Lin et al. [7] obtained up to 99.8 % ee for the hydrogenation of a range of b-aryl b-ketoesters. The highest TON (10 000) was achieved by Saito and co-workers [8] in the asymmetric hydrogenation of methyl 3-oxo-3-phenylpropanoate. Note that chiral rhodium or iridium complexes, which efficiently catalyze olefin and imine hydrogenation, are seldom used for the asymmetric hydrogenation of b-ketoesters.[9] Furthermore, chiral [RuCl 2 (diphosphine)(diamine)] complexes, which catalyze the hydrogenation of simple ketones extremely efficiently, are also inert for the hydrogenation of b-ketoesters.[10] The major reason for the inertness may be that the strong base, such as KOtBu, that is required for activation of the [RuCl 2 (diphosphine)(diamine)] catalysts enolizes the b-ketoester substrates instead of activating the catalysts.Recently, we developed chiral iridium catalysts containing a chiral SpiroPAP ligand, and these catalysts show excellent enantioselectivity (up to 99.9 % ee) and an extremely high TON (as high as 4 550 000) for the hydrogenation of simple ketones.[11] These Ir/SpiroPAP catalysts are likely to have a "metal-ligand bifunctional catalysis" mechanism, similar to the [RuCl 2 (diphosphine)(diamine)] catalysts.[12] The aromatic N À H of the Ir/SpiroPAP catalysts is more acidic than the aliphatic NÀH of [RuCl 2 (diphosphine)(diamine)] catalysts (the proton resonances of the NH or NH 2 group of the catalysts are as follows:.3 and 3.5 ppm (C 6 D 6 ) [13] ), thus indicating that the Ir/SpiroPAP catalysts may be more easily activated with a relatively weak base such as the enolate salt of a b-ketoester. To confirm this possibility, we tested Ir/SpiroPAP catalysts for the hydrogenation of bketoesters and found that the catalysts were...

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An Additional Coordination Group Leads to Extremely Efficient Chiral Iridium Catalysts for Asymmetric Hydrogenation of Ketones

Abstract: What a turnover! An efficient chiral iridium catalyst that bears a tridentate spiro aminophosphine ligand catalyzes the asymmetric hydrogenation of ketones with excellent enantioselectivities (up to 99.9 % ee) and extremely high turnover numbers (TONs; as high as 4 550 000).

Cited by 221 publications

References 36 publications

Ketone Hydrogenation with Iridium Complexes with “non N–H” Ligands: The Key Role of the Strong Base

Ketone Hydrogenation with Iridium Complexes with “non N–H” Ligands: The Key Role of the Strong Base

Toward Ideal Asymmetric Catalysis

Chiral Iridium Catalysts Bearing Spiro Pyridine‐Aminophosphine Ligands Enable Highly Efficient Asymmetric Hydrogenation of β‐Aryl β‐Ketoesters

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