78398-36-4Relevant academic research and scientific papers
Asymmetric Transfer Hydrogenation of (Hetero)arylketones with Tethered Rh(III)-N-(p-Tolylsulfonyl)-1,2-diphenylethylene-1,2-diamine Complexes: Scope and Limitations
Zheng, Long-Sheng,Llopis, Quentin,Echeverria, Pierre-Georges,Férard, Charlène,Guillamot, Gérard,Phansavath, Phannarath,Ratovelomanana-Vidal, Virginie
, p. 5607 - 5615 (2017/06/07)
A series of new tethered Rh(III)/Cp? complexes containing the N-(p-tolylsulfonyl)-1,2-diphenylethylene-1,2-diamine ligand have been prepared, characterized, and evaluated in the asymmetric transfer hydrogenation (ATH) of a wide range of (hetero)aryl ketones. The reaction was performed under mild conditions with the formic acid/triethylamine (5:2) system as the hydrogen source and provided enantiomerically enriched alcohols with good yields and high to excellent enantioselectivities. Although the nature of the substituents on the phenyl tethering ring did not alter the stereochemical outcome of the reaction, complexes bearing electron-donating groups exhibited a higher catalytic activity than those having electron-withdrawing groups. A scale-up of the ATH of 4-chromanone to the gram scale quantitatively delivered the reduced product with excellent enantioselectivity, demonstrating the potential usefulness of these new complexes.
Synthesis, characterization and use of a new tethered Rh(III) complex in asymmetric transfer hydrogenation of ketones
Echeverria, Pierre-Georges,Férard, Charlène,Phansavath, Phannarath,Ratovelomanana-Vidal, Virginie
, p. 95 - 99 (2015/02/05)
A new Rh(III) complex containing the TsDPEN ligand and an η6-arene connected through a carbon tether is reported. The asymmetric transfer hydrogenation of a series of ketones catalyzed by this complex using the formic acid/triethylamine system provided the corresponding alcohols with complete conversions and a high level of enantioselectivity.
Asymmetric synthesis of optically active methyl-2-benzamido-methyl-3-hydroxy-butyrate by robust short-chain alcohol dehydrogenases from Burkholderia gladioli
Chen, Xiang,Liu, Zhi-Qiang,Huang, Jian-Feng,Lin, Chao-Ping,Zheng, Yu-Guo
, p. 12328 - 12331 (2015/07/27)
Three short-chain alcohol dehydrogenases from Burkholderia gladioli were discovered for their great potential in the dynamic kinetic asymmetric transformation of methyl 2-benzamido-methyl-3-oxobutanoate, and their screening against varied organic solvents and substrates. This is the first report of recombinant enzymes capable of achieving this reaction with the highest enantio- and diastereo-selectivity.
Amino acid derived amides and hydroxamic acids as ligands for asymmetric transfer hydrogenation in aqueous media
Ahlford, Katrin,Adolfsson, Hans
experimental part, p. 1118 - 1121 (2012/01/15)
Amides and hydroxamic acids derived from α-amino acids were evaluated as ligands in combination with rhodium and iridium half-sandwich complexes in asymmetric transfer hydrogenation (ATH) of ketones. The reactions were performed in aqueous media using lithium formate as hydride source. The catalyst systems turned out to be highly efficient and ee's up to 90% were obtained.
Chiral pincer ruthenium and osmium complexes for the fast and efficient hydrogen transfer reduction of ketones
Baratta, Walter,Benedetti, Fabio,Del Zotto, Alessandro,Fanfoni, Lidia,Felluga, Fulvia,Magnolia, Santo,Putignano, Elisabetta,Rigo, Pierluigi
experimental part, p. 3563 - 3570 (2010/10/03)
A series of chiral HCNN ligands ((S)-1b-g) (S)-2-(1-aminoethyl)-6-(aryl) pyridine (aryl = 4-MeO-phenyl, 1b; 4-CF3-phenyl, 1c; 3,5-di-Me-phenyl, 1d; 3,5-di-CF3-phenyl, 1e; 1-naphthyl, 1f; 2-naphthyl, 1g) were synthesized starting from commercial 2-acetyl-6- bromopyridine (2), by a chemoenzymatic method involving the dynamic kinetic resolution of the corresponding secondary alcohol (rac-3). The conversion of the resulting (R)-3, obtained in 98% ee, into the homochiral amine ((S)-6), followed by Suzuki coupling with the appropriate arylboronic acids 7b-g, gave access to (S)-1b-g, isolated in 97% ee, with an overall yield up to 50%. The in situ generated pincer complexes [MCl(CNN)(PP)] (M = Ru, Os; PP = Josiphos diphosphine), prepared from [MCl2(PPh3)3], (R,S)-Josiphos diphosphines, and the ligands (S)-1b-g, were found to efficiently catalyze the asymmetric transfer hydrogenation of acetophenone in 2-propanol at 60 °C and in the presence of NaOiPr. On the basis of these data, the 2-naphthyl ruthenium and osmium derivatives [RuCl(CNN)((R,S)-Josiphos*] (8) (HCNN = (S)-1g) and [OsCl(CNN)(PP)] (PP = (R,S)-Josiphos, 9, and (R,S)-Josiphos*, 10) were isolated from [MCl2(PPh 3)3], (R,S)-Josiphos diphosphines, and the ligand (S)-1g. Complexes 8 and 10, displaying the correctly matched chiral PP and CNN - ligands, are highly active and productive catalysts for the transfer hydrogenation of alkyl aryl ketones and methyl pyridyl ketones with TOF = 105-106 h-1, using 0.005 mol % of catalysts and achieving up to 99% ee. The comparison of the catalytic activity of these pincer complexes shows that Ru and Os derivatives display similar rate and enantioselectivity.
STEREOCHEMISTRY OF PHOTOSOLVOLYSIS OF A CHIRAL, 18O-LABELED 1-ARYLETHYL ACETATE
Jaeger, David A.,Angelos, George H.
, p. 803 - 806 (2007/10/02)
The stereochemistry of photosolvolysis of (R)-(+)-1-(3,5-dimethoxyphenyl)ethyl acetate-ether-18O in methanol-water and 2,2,2-trifluoroethanol has been determined.An ion pair intermediate was detected in the latter solvent.
