Transfer Hydrogenation In Water Research Articles

Photocatalytic Transfer Hydrogenation in Water: Insight into Mechanism and Catalyst Speciation

Photocatalytic Transfer Hydrogenation in Water: Insight into Mechanism and Catalyst Speciation

Ru-Pd Thermoresponsive Nanocatalyst Based on a Poly(ionic liquid) for Highly Efficient and Selectively Catalyzed Suzuki Coupling and Asymmetric Transfer Hydrogenation in the Aqueous Phase.

The development of intelligent polymeric materials to precisely control the catalytic sites of heterogeneous catalysts and enable highly efficient catalysis of a cascade reaction is of great significance. Here, the utilization of a polymer ionic liquid (PIL) containing two different anions facilitates the preparation of Ru-Pd catalysts with controllable phase transition temperatures and hydrophilic and hydrophobic surfaces. The combined multifunctionality, synergistic effects, micellar effects, aggregation effects, and temperature responsiveness of the nanocatalyst render it suitable for promoting selectively catalyzed Suzuki coupling and asymmetric transfer hydrogenation in water. Above the lower critical solution temperature (LCST) of the catalyst, it catalyzes only the coupling reaction with a high turnover number (TON) of up to 999.0. Below the LCST, the catalyst catalyzes only the asymmetric transfer hydrogenation with good catalytic activity and enantioselectivity. It is important that the catalyst can be simply and effectively recovered and recycled at least 10 times without significant loss of catalytic activity and enantioselectivity. This study also highlights the superiority of multifunctional heterogeneous catalysts based on PILs, which not only overcome limitations associated with low activity of heterogeneous catalysts but also realize selective reactions according to a temperature change, thereby improving the reactivity and enantioselectivity in multiple organic transformations.

Transfer Hydrogenation in Water.

This article provides an account of our group's efforts in developing aqueous-phase transfer hydrogenation reactions. It is comprised of mainly two parts. The first part concentrates on asymmetric transfer hydrogenation in water, enabled by Noyori-Ikariya catalysts, while the second part is concerned with the achiral version of the reaction catalysed by a new class of catalysts, iridacycles. A range of substrates are featured, including various carbonyl compounds and N-heterocycles.

Noyori–Ikariya catalyst supported on tetra-arylphosphonium salt for asymmetric transfer hydrogenation in water

An easily prepared, low weight, recyclable supported Noyori–Ikariya catalyst is described. The ruthenium precatalyst provides excellent conversions and high enantioselectivities for the asymmetric transfer hydrogenation of ketones in water.

Transfer Hydrogenation (pH Independent) of Ketones and Aldehydes in Water with Glycerol: Ru, Rh, and Ir Catalysts with a COOH Group near the Metal on a (Phenylthio)methyl-2-pyridine Scaffold

The reactions of 2-(pyridine-2-ylmethylsulfanyl)benzoic acid (L) with [(η5-Cp*/η6-benzene)MCl(μ-Cl)]2, (benzene, M = Ru; Cp*, M = Rh, Ir) at room temperature followed by treatment with NH4PF6 result in a new class of water-soluble half-sandwich complexes [(η5Cp*/η6-benzene)M(L)Cl][PF6] (1–3, respectively, for M = Ru, Rh, Ir). Their characteristic HR-MS and 1H and 13C{1H} NMR spectra have been found. The single-crystal structures of 1–3 have been established with X-ray crystallography. The Ru–S, Rh–S, and Ir–S bond lengths are 2.4079(6), 2.3989(10), and 2.3637(14) A, respectively. Complexes 1–3 have been found to be efficient for catalytic transfer hydrogenation (TH) of carbonyl compounds in water with glycerol as a hydrogen donor. Glycerol has been explored for TH in water for the first time. The efficiency in water of other hydrogen sources, viz. HCOOH, citric acid, ascorbic acid, and 2-propanol, is less and/or is pH dependent. Catalysis with glycerol as a hydrogen source is pH independent and appears to...

ChemInform Abstract: Synthesis of (R)‐Tembamide and (R)‐Aegeline via Asymmetric Transfer Hydrogenation in Water.

ChemInformVolume 45, Issue 20 Preparative Organic Chemistry ChemInform Abstract: Synthesis of (R)-Tembamide and (R)-Aegeline via Asymmetric Transfer Hydrogenation in Water. Norma A. Cortez, Norma A. Cortez Cent. Grad. Invest., Inst. Tecnol., 22000 Tijuana, Mex.Search for more papers by this authorGerardo Aguirre, Gerardo Aguirre Cent. Grad. Invest., Inst. Tecnol., 22000 Tijuana, Mex.Search for more papers by this authorMiguel Parra-Hake, Miguel Parra-Hake Cent. Grad. Invest., Inst. Tecnol., 22000 Tijuana, Mex.Search for more papers by this authorRatnasamy Somanathan, Ratnasamy Somanathan Cent. Grad. Invest., Inst. Tecnol., 22000 Tijuana, Mex.Search for more papers by this author Norma A. Cortez, Norma A. Cortez Cent. Grad. Invest., Inst. Tecnol., 22000 Tijuana, Mex.Search for more papers by this authorGerardo Aguirre, Gerardo Aguirre Cent. Grad. Invest., Inst. Tecnol., 22000 Tijuana, Mex.Search for more papers by this authorMiguel Parra-Hake, Miguel Parra-Hake Cent. Grad. Invest., Inst. Tecnol., 22000 Tijuana, Mex.Search for more papers by this authorRatnasamy Somanathan, Ratnasamy Somanathan Cent. Grad. Invest., Inst. Tecnol., 22000 Tijuana, Mex.Search for more papers by this author First published: 28 April 2014 https://doi.org/10.1002/chin.201420023Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume45, Issue20May 20, 2014 RelatedInformation

Synthesis of (R)-tembamide and (R)-aegeline via asymmetric transfer hydrogenation in water

The synthesis of (R)-tembamide and (R)-aegeline via asymmetric transfer hydrogenation involving enantioenriched monosulfonamide–RhCp∗ complex in aqueous sodium formate as hydride donor is described.

ChemInform Abstract: Hydrogenation and Transfer Hydrogenation in Water

AbstractReview: 346 refs.

Phosphonate-containing polystyrene copolymer-supported Ru catalyst for asymmetric transfer hydrogenation in water

A series of phosphonate-containing copolystyrenes with chiral ligand (1R,2R)-(+)-N1-toluenesulfonyl-1,2-diphenylethylene-1,2-diamine were prepared by radical copolymerization. The supported Ru catalysts with excellent catalytic performances (94–98% yields, 93.9–97.8% ee and 100% chemoselectivity) in aqueous asymmetric transfer hydrogenation could be easily recycled by centrifugal separation.

ChemInform Abstract: pH‐Independent Transfer Hydrogenation in Water: Catalytic, Enantioselective Reduction of β‐Keto Esters.

AbstractIn the presence of an optimized moisture‐ and air‐stable iridium catalyst, aromatic/heteroaromatic ketoesters are reduced by formic acid/sodium formate in excellent yields and enantioselectivities.

Iridium-Catalyzed Asymmetric Transfer Hydrogenation in Water

Iridium-Catalyzed Asymmetric Transfer Hydrogenation in Water

PH-Independent Transfer Hydrogenation in Water: Catalytic, Enantioselective Reduction of β-Keto Esters

A pH-independent asymmetric transfer hydrogenation of β-keto esters in water with formic acid/sodium formate is described. The reaction is conducted open to air and gives access to β-hydroxy esters in excellent yields and selectivities.

Total synthesis of the anti-inflammatory lipid mediator Resolvin E2

The total synthesis of Resolvin E2, an endogenous lipid mediator of the resolution of inflammation derived from eicosapentaenoic acid, has been achieved. The chiral hydroxy-groups at C5 and C18 were generated in a simple, efficient, and environmentally friendly manner via an asymmetric Noyori transfer hydrogenation in water using sodium formate as a reducing agent. Pd0/CuI Sonogashira couplings of the three key fragments and Zn(Cu/Ag) reduction completed the synthesis of Resolvin E2.

Transfer Hydrogenation in Water via a Ruthenium Catalyst with OH Groups near the Metal Center on a bipy Scaffold

The new ligand 6,6′-dihydroxy-2,2′-bipyridyl (dhbp) was synthesized via its tautomer, and this provides an efficient route to novel metal complexes of dhbp. In ruthenium complexes of dhbp, these OH groups enhance water solubility and may play a role in aqueous transfer hydrogenation with formate/formic acid as the hydrogen source. A series of cationic catalysts, [(η6-arene)Ru(N,N)Cl]Cl (arene = cymene, C6Me6; N,N = bipyridyl with OH, OMe, or H at the 6- and 6′-positions), were synthesized, fully characterized, and tested for transfer hydrogenation activity in various polar protic media. In aqueous media (90/10 water/methanol), Ru complexes of dhbp outperform the other catalysts tested (all at 1 mol %), and high percentage conversion of aromatic ketones to the corresponding alcohols is observed in 6 h. The OH groups appear to be essential for use of water as a green solvent and can potentially allow for metal–ligand bifunctional catalysis.

Single-Chain Folding of Polymers for Catalytic Systems in Water

Enzymes are a source of inspiration for chemists attempting to create versatile synthetic catalysts. In order to arrive at a polymeric chain carrying catalytic units separated spatially, it is a prerequisite to fold these polymers in water into well-defined compartmentalized architectures thus creating a catalytic core. Herein, we report the synthesis, physical properties, and catalytic activity of a water-soluble segmented terpolymer in which a helical structure in the apolar core is created around a ruthenium-based catalyst. The supramolecular chirality of this catalytic system is the result of the self-assembly of benzene-1,3,5-tricarboxamide side chains, while the catalyst arises from the sequential ruthenium-catalyzed living radical polymerization of the different monomers followed by ligand exchange. The polymers exhibit a two-state folding process and show transfer hydrogenation in water.

ChemInform Abstract: Asymmetric Transfer Hydrogenation in Water with Platinum Group Metal Catalysts: Rapid Reactions and High Enantioselectivities Achieved for Carbonyl Bond Reduction

AbstractReview: 133 refs.

ChemInform Abstract: Transfer Hydrogenation in Water: Enantioselective, Catalytic Reduction of α‐Cyano and α‐Nitro Substituted Acetophenones.

AbstractThe reaction applies formic acid as a reductant and proceeds under aqueous aerobic conditions to afford the resulting alcohols with high yields and enantioselectivities.

Transfer Hydrogenation in Water: Enantioselective, Catalytic Reduction of α-Cyano and α-Nitro Substituted Acetophenones

Catalytic reduction of alpha-substituted acetophenones under conditions involving asymmetric transfer hydrogenation in water is described. The reaction is conducted in water and open to air, and formic acid is used as reductant.

ChemInform Abstract: Transfer Hydrogenation in Water: Enantioselective, Catalytic Reduction of (E)‐β,β‐Disubstituted Nitroalkenes.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 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 in Water with Platinum Group Metal Catalysts

Asymmetric transfer hydrogenation (ATH) is the reduction of prochiral compounds with a hydrogen donor other than hydrogen gas in the presence of a chiral catalyst. The asymmetric reduction of a wide variety of ketone and aldehyde substrates has been carried out in water using catalysts based on complexes of ruthenium(II), rhodium(III) and iridium(III), affording fast reaction rates and good enantioselectivities without the use of organic solvents and with easy separation of catalyst and product. For ATH of ketones, the Rh(III) complexes appear to perform better than the Ru(II) and Ir(III) complexes in terms of activity, enantioselectivity and substrate scope. However, their performance varies with the choice of ligands, and simple Ir(III)-diamine complexes were found to be excellent catalysts for the reduction of aldehydes.