Imidazolium ion tethered TsDPENs as efficient water-soluble ligands for rhodium catalyzed asymmetric transfer hydrogenation of aromatic ketones

Kang, Guowei; Lin, Silong; Shiwakoti, Atul; Ni, Bukuo

doi:10.1016/j.catcom.2014.08.006

Cited by 20 publications

(19 citation statements)

References 33 publications

(29 reference statements)

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“…19−21 Several studies reported increased water solubility of the TsDPEN structural motif after functionalization with cationic groups, including modification with heterocyclic or trialkylammonium cations. 22,23 This approach, featuring cationic surfactant-type catalysts, becomes especially attractive concerning the enantioselective transfer hydrogenation of aliphatic ketones, which has been challenging, with only few successful examples in the literature. 24 Inspired by these works and based on the results previously obtained with amino alcohol based chiral ionic ligand structures in our group, we herein report the extension of this modular ligand design to diamine based scaffolds (Figure 1).…”

Section: ■ Introductionmentioning

confidence: 99%

“…The implementation of cationic groups inspired by ionic liquids based on ammonium, imidazolium or pyridinium cations has the advantage of facile ligand modification. The variation of alkyl chain length or counterion allows to fine-tune properties to the given reaction conditions while simultaneously solubilizing the ligand in polar reaction media such as water or ionic liquids. − Several studies reported increased water solubility of the TsDPEN structural motif after functionalization with cationic groups, including modification with heterocyclic or trialkylammonium cations. , This approach, featuring cationic surfactant-type catalysts, becomes especially attractive concerning the enantioselective transfer hydrogenation of aliphatic ketones, which has been challenging, with only few successful examples in the literature . Inspired by these works and based on the results previously obtained with amino alcohol based chiral ionic ligand structures in our group, we herein report the extension of this modular ligand design to diamine based scaffolds (Figure ).…”

Section: Introductionmentioning

confidence: 99%

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Ion-Tagged Chiral Ligands for Asymmetric Transfer Hydrogenations in Aqueous Medium

Pálvölgyi

Bitai

Zeindlhofer

et al. 2019

ACS Sustainable Chem. Eng.

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We report the design and synthesis of novel ion-tagged chiral ligands for asymmetric transfer hydrogenation (ATH) in aqueous medium. Based on (R,R)-1,2-diphenylethylene diamine (DPEN) as structural motif, a straightforward three-step protocol was developed that gave access to novel chiral ligands with carbamate-substructure and pyridinium headgroup. The careful optimization of steric and electronic properties in combination with the adaption of solubility via choice of the anion gave a set of chiral and water-soluble ligands for use in ruthenium-catalyzed asymmetric transfer hydrogenations in aqueous medium. Eventually, a pool of aliphatic and aromatic ketones as well as two imine substrates were reduced with excellent isolated yields up to 95% and enantioselectivities >90% ee under environmentally benign conditions in the absence of additional surfactants.

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Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ion-Tagged Chiral Ligands for Asymmetric Transfer Hydrogenations in Aqueous Medium

Pálvölgyi

Bitai

Zeindlhofer

et al. 2019

ACS Sustainable Chem. Eng.

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“…(1R,2R)-N-Boc-N'-(4-bromomethylphenylsulfonyl)-1,2-diph enylethylenediamine was synthesized according to the reported method [23]. tert-Butyl [(1R,2R)-2-amino-1,2diphenylethyl]carbamate (1.87 g, 6.0 mmol) in 20 mL of DCM was added to Et3N (0.84 mL, 6.0 mmol).…”

Section: Synthesis Of (1r2r)-n-boc-n'-(4-bromomethylphenylsulfonyl)-12-diphenylethylenediaminementioning

confidence: 99%

Development of efficient solid chiral catalysts with designable linkage for asymmetric transfer hydrogenation of quinoline derivatives

Ren

Tao

et al. 2021

Chinese Journal of Catalysis

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Developing chiral solid catalysts for asymmetric catalysis is desirable for the elimination of homogeneous catalysis flaws but remains an immense challenge. Herein, we report the immobilization of TsDPEN on SBA-15 with an ionic liquid (IL) linkage via the one-pot reaction of imidazole-TsDPEN-N-Boc with 3-(trimethoxysilyl)propyl bromide in the SBA-15 mesopores. After coordination to Rh, the chiral solid catalysts could efficiently catalyze quinoline transfer hydrogenation, achieving 97% conversion with 93% ee, which was comparable to their homogeneous counterparts. The chiral solid catalyst with the IL linkage afforded much higher turnover frequency than that without the IL linkage (93 h -1 vs. 33 h -1 ), attributed to the phase transfer and formate-enriching ability of the IL linkage. Furthermore, the effect of the pH on the reaction rate of the solid catalyst was investigated, preventing reaction rate retardation during the catalytic process. The tuning of the linkage group is an efficient approach for catalytic activity improvement of immobilized chiral catalysts.

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“…139 Also with the same rhodium catalyst, the water soluble triamine ligand 174 was an excellent one for the ATH of several aromatic and heterocyclic ketones in water and with sodium formate as the reductant. The ATH of aromatic ketones was carried out satisfactorily in aqueous medium with the same rhodium catalyst and the ligand 175 with low catalyst loading and sodium formate as the hydrogen source, giving the expected alcohols in general with high yields and enantioselectivities.…”

Section: Water As Solventmentioning

confidence: 99%

Catalytic asymmetric transfer hydrogenation of ketones: recent advances

Foubelo

Nájera

Yus

2015

Tetrahedron: Asymmetry

204

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Abstract-In this review article we will consider the main processes on asymmetric transfer hydrogenation (ATH) of ketones from 2008 up today. The most effective organometallic compounds (derived from Ru, Rh, Ir, Fe, Os, Ni, Co, and Re) and chiral ligands (derived from amino alcohols, diamines, sulphur-and phosphorous-containing compounds, as well as heterocyclic systems) will be shown paying special attention to functionalized substrates, tandem reactions, processes under nonconventional conditions, supported catalysts, dynamic kinetic resolutions (DKR), the use of water as a green solvent, theoretical and experimental studies on reaction mechanisms, enzymatic processes and finally applications to the total synthesis of biologically active organic molecules. _____________________________________________________________________________________

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Imidazolium ion tethered TsDPENs as efficient water-soluble ligands for rhodium catalyzed asymmetric transfer hydrogenation of aromatic ketones

Cited by 20 publications

References 33 publications

Ion-Tagged Chiral Ligands for Asymmetric Transfer Hydrogenations in Aqueous Medium

Ion-Tagged Chiral Ligands for Asymmetric Transfer Hydrogenations in Aqueous Medium

Development of efficient solid chiral catalysts with designable linkage for asymmetric transfer hydrogenation of quinoline derivatives

Catalytic asymmetric transfer hydrogenation of ketones: recent advances

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