Aromatic Ketones In Water Research Articles

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

An imidazolium ion tethered TsDPEN has been synthesized readily and used as a water-soluble ligand for [Cp*RhCl2]2 catalyzed asymmetric transfer hydrogenation (ATH) of aromatic ketones in water. This process provided the secondary alcohols in moderate to excellent conversions (up to 100%) with high enantioselectivities (up to 98% ee) under mild reaction conditions without adding any surfactants. The catalytic system is highly effective with the substrate to catalyst (S/C) ratio of 500 and low hydride donor loading of 1.5equiv. of HCO2Na. The procedure presented is simple and makes this method suitable for practical use.

Screening of a library of hemisalen ligands in asymmetric H-transfer: Reduction of aromatic ketones in water

A library of chiral hemisalen ligands (30) was realized. The ligands were synthesized by the condensation of salicylaldehyde derivatives with amino-alcohols (amino-indanol or substituted amino-ethanol) and characterized. These ligands associated with ruthenium (II) precursors were tested on the asymmetric transfer hydrogenation (ATH) of aromatic ketones by sodium formate in water. The different substituent pattern on the ligand (electronic and hindrance effects on different positions) as well as the ruthenium precursor were investigated. The best compromise in terms of conversion and chiral induction led to the complex [RuCl2(mesitylene)]2 coordinated to (1S,2R)-1-((E)-(3-(dimethyl(phenyl)silyl)-2-hydroxy-5-methoxy benzylidene) amino)-2,3-dihydro-1H-inden-2-ol (L25). It reduces acetophenone in 95% yield and 91% ee in 18 h at 30°C. © 2013 Academie des sciences.

Immobilization of chiral Rh catalyst on glass and application to asymmetric transfer hydrogenation of aryl ketones in aqueous media

A chiral catalyst, Cp*RhTsDPEN (Cp* = pentamethyl cyclopentadiene, TsDPEN = substitutive phenylsulfonyl-1,2-diphenylethylenediamine), was synthesized and immobilized at the surface of glass. The immobilized catalyst exhibited good catalytic efficiency for asymmetric transfer hydrogenation of aromatic ketones in water with HCOONa as hydrogen source.

The synthesis of a new nitrogen joined N-PEG-TsDPEN ligand and its application in asymmetric transfer hydrogenation of ketones in neat water

A new polyethylene glycol (PEG) supported ligand, with the PEG chain attached to the nitrogen of TsDPEN, was synthesized using a very simple procedure. The Ru-catalyzed asymmetric transfer hydrogenation of various aromatic ketones in water was investigated with this chiral ligand. High chemical yields and enantioselectivities were obtained under very mild conditions. In addition, the chiral ligand was easily recycled several times and this catalyst was especially suitable for the preparation of chiral tetrahydronaphthalen-1-ol and 2,3-dihydro-1H-inden-1-ol (up to 98% conversion with 99% ee). The latter product can be used as the key intermediate for the synthesis of neuroprotective and anti-AChE agents Rasagiline and Ladostigil.

ChemInform Abstract: Ruthenium(II)‐Catalyzed Asymmetric Transfer Hydrogenation of Aromatic Ketones in Water Using Novel Water‐Soluble Chiral Monosulfonamide Ligands.

AbstractA series of ligands of type (I) and (II) is synthesized.

Polyethylene glycol‐bound Ru catalyst for asymmetric transfer hydrogenation of aromatic ketones in water

AbstractA new polyethylene glycol‐supported chiral monosulfonamide was synthesized from (R,R)‐1,2‐diaminocyclohexane and shown to act as a ligand for ruthenium(II)‐catalyzed asymmetric transfer hydrogenation of aromatic ketones in neat water using sodium formate as the hydrogen source. Good enantioselectivities were obtained and the catalyst could be easily separated from the reaction mixture and reused several times. Copyright © 2011 John Wiley & Sons, Ltd.

Microwave-assisted synthesis of α-hydroxy aromatic ketones from α-bromo aromatic ketones in water

Abstract A reaction of α-bromo aromatic ketones in water with microwave irradiation gave the corresponding α-hydroxy aromatic ketones in good yields. The use of microwaves was found to significantly improve yields and shorten the reaction time. This reaction afforded a very clean, convenient method for the synthesis of α-hydroxy aromatic ketones.

Ruthenium(II)‐catalyzed asymmetric transfer hydrogenation of aromatic ketones in water using novel water‐soluble chiral monosulfonamide ligands

AbstractNovel water‐soluble analogues of Noyori's (R,R)‐N‐(p‐tolylsulfonyl)‐1,2‐diphenylethyl‐ enediamine and Knochel's (R,R)‐N‐(p‐tolylsulfonyl)‐1,2‐diaminocyclohexane, containing an additional quaternary ammonium group, have been synthesized. The ruthenium catalysts prepared in situ by reacting chiral monosulfonamides with [RuCl2(p‐cymene)]2 afforded high conversion rates and enantiomeric excess (ee) values in the asymmetric transfer hydrogenation of aromatic ketones in aqueous HCOONa. Furthermore, the catalyst could be easily recovered and reused at least five times without obvious loss of ee value. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:505–514, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20641

ChemInform Abstract: Asymmetric Transfer Hydrogenation of Aromatic Ketones in Water Using a Polymer‐Supported Chiral Catalyst Containing a Hydrophilic Pendant Group.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Asymmetric Transfer Hydrogenation of Aromatic Ketones in Water using a Polymer‐Supported Chiral Catalyst Containing a Hydrophilic Pendant Group

AbstractHydrophilic polymers having pendant groups of carboxylates or sulfonates have been used as a polymer support for chiral 1,2‐diamine monosulfonamides. The polymeric chiral complex prepared from the polymer‐supported chiral ligand with ruthenium dichloride⋅p‐cymene was used in the asymmetric transfer hydrogenation of prochiral ketones in water. The balance between hydrophilicity and hydrophobicity of the polymer support influenced both the reactivity and the enantioselectivity of the reaction in water. The chiral polymeric complex having a quaternary ammonium salt structure as the pendant group worked well in water. In most cases the polymer‐supported catalyst having a quaternary ammonium sulfonate pendant group showed superior enantioselectivity compared to the corresponding non‐supported model catalyst in the solution system. The polymeric catalysts can be reused without loss of catalytic activity.

Asymmetric transfer hydrogenation of ketones with a polyethylene glycol bound Ru catalyst in water

A new polyethylene glycol supported Ru catalyst was synthesized and applied in the asymmetric transfer hydrogenation of various aromatic ketones in water with high chemical yields and enantioselectivities without adding any surfactants. The catalyst could be easily recycled several times without a significant loss of enantioselectivity and activity.

Highly Efficient Chiral PNNP Ligand for Asymmetric Transfer Hydrogenation of Aromatic Ketones in Water.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Highly efficient chiral PNNP ligand for asymmetric transfer hydrogenation of aromatic ketones in water

Chiral PNNP ligand II and [IrHCl 2(COD)] 2 were applied for the first time in the asymmetric transfer hydrogenation of aromatic ketones with HCOONa in water, giving the corresponding optical alcohols in high yield and excellent enantioselectivity (up to 99% ee). Particularly, the reduction of propiophenone proceeded smoothly at a substrate to catalyst molar ratio of 8000, without compromising the ee values obtained.

Design of novel polymer-supported chiral catalyst for asymmetric transfer hydrogenation in water

New polymer-supported chiral sulfonamides containing sulfonated pendant group have been synthesized. Chiral catalyst prepared from the new polymer-support is more effective for asymmetric transfer hydrogenation of aromatic ketones in water compared to that prepared from conventional polystyrene-support. Polymer-supported catalysts containing quaternary ammonium salt as a pendant increased not only the reactivity but also the enantioselectivity in asymmetric transfer hydrogenation in water. Moreover, this type of polymer can be reused without loss of the catalytic activity.

A Remarkably Effective Catalyst for the Asymmetric Transfer Hydrogenation of Aromatic Ketones in Water and Air.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Insight into and Practical Application of pH‐Controlled Asymmetric Transfer Hydrogenation of Aromatic Ketones in Water

Insight into and Practical Application of pH‐Controlled Asymmetric Transfer Hydrogenation of Aromatic Ketones in Water

Insight into and Practical Application of pH‐Controlled Asymmetric Transfer Hydrogenation of Aromatic Ketones in Water

Eine viel schnellere, enantioselektivere und produktivere Katalyse der asymmetrischen Transferhydrierung aromatischer Ketone gelingt mit dem Noyori-Ikariya-Ru-(Ts-dpen)-Katalysator, wenn er in Wasser bei nahezu neutralen pH-Werten eingesetzt wird (siehe Schema). Bei niedrigen pH-Werten ist die Reaktion weit weniger effizient und verläuft vermutlich nach einem anderen Mechanismus.

A remarkably effective catalyst for the asymmetric transfer hydrogenation of aromatic ketones in water and air

A Rh(III) complex generated in situ from [Cp*RhCl2]2 and (1R,2R)-N-(p-toluenesulfonyl)-1,2-cyclohexanediamine (TsCYDN) serves as a remarkably effective, robust catalyst for the asymmetric transfer hydrogenation of aromatic ketones by HCOONa in water in air, affording alcohols in up to 99% ee.

Accelerated Asymmetric Transfer Hydrogenation of Aromatic Ketones in Water.

Asymmetric transfer hydrogenation of various simple aromatic ketones by the Ru-TsDPEN catalyst was shown to be feasible in aqueous HCOONa without calling for any catalyst modification, furnishing ee's of up to 95% and significantly faster rates than in the HCOOH–NEt3 azeotrope.

Accelerated asymmetric transfer hydrogenation of aromatic ketones in water.

Asymmetric transfer hydrogenation of various simple aromatic ketones by the Ru-TsDPEN catalyst was shown to be feasible in aqueous HCOONa without calling for any catalyst modification, furnishing ee's of up to 95% and significantly faster rates than in the HCOOH-NEt(3) azeotrope.