104974-60-9Relevant academic research and scientific papers
Highly activity asymmetric hydrogenation of enones catalyzed by iridium complexes with chiral diamines and achiral phosphines
Chen, Hua,Gao, Xiuli,Jiang, Jian,Li, Chun,Li, Li,Lu, Xunhua,Wang, Mengna,Zhang, Lin,Zhang, Ling
, (2020)
A selective asymmetric hydrogenation of enones has been well established by using an iridium complex composed of cheap phosphine ligands and cinchona alkaloids derivatives as catalyst. A wide range of allylic alcohol products could be obtained in high chemoselectivities (up to 99.6%), enantioselectivities (70.1% ee) and high activities (up to 3.64 × 104(1/h) TOF). This catalytic system opens a new way of selective asymmetric hydrogenation and the method can be of practical value.
Characterization of the Main Radical and Products Resulting from a Reductive Activation of the Antimalarial Arteflene (Ro 42-1611)
Cazelles, Jerome,Robert, Anne,Meunier, Bernard
, p. 6776 - 6781 (1999)
The peroxide-containing antimalarial drug arteflene (Ro 42-1611) generates an alkyl radical after the reductive homolytic cleavage of the peroxide bond in the presence of a heme model MnII(TPP). This alkyl radical has been trapped by TEMPO, and the different products of the reduction activation of arteflene have been characterized. These data suggest that, in these experimental conditions, arteflene is not a significant alkylating agent compared to artemisinin, a trioxane-containing antimalarial drug.
Production of enantiomerically enriched chiral carbinols using whole-cell biocatalyst
Bayda?, Yasemin,Kalay, Erbay,?ahin, Engin
, p. 29 - 37 (2022)
Biocatalytic asymmetric reduction of ketone is an efficient method for the production of chiral carbinols. The study indicates selective bioreduction of different ketones (1–8) to their respective (R)-alcohols (1a–8a) in low to high selectivity (0- >99%) with good yields (11–96%). In this work, whole-cell of Lactobacillus kefiri P2 catalysed enantioselective reduction of various prochiral ketones was investigated. (R)-4-Phenyl-2-butanol 2a, which is used as a precursor to antihypertensive agents and spasmolytics (anti-epileptic agents), was obtained using L kefiri P2 in 99% conversion and 91% enantiomeric excess (ee). Moreover, bioreduction of 2-methyl-1-phenylpropan-1-one substrate 8, containing a branched alkyl chain and difficult to asymmetric reduction with chemical catalysts as an enantioselective, to (R)-2-methyl-1-phenylpropan-1-ol (8a) in enantiomerically pure form was carried out in excellent yield (96%). The gram-scale production was carried out, and 9.70 g of (R)-2-methyl-1-phenylpropan-1-ol (8a) in enantiomerically pure form was obtained in 96% yield. Also especially, the yield and gram scale of (R)-2-methyl-1-phenylpropan-1-ol (8a) synthesised through catalytic asymmetric reduction using the biocatalyst was the highest report so far. The efficiency of L kefiri P2 for the conversion of the substrates and ee of products were markedly influenced by the steric factors of the substrates. This is a cheap, clean and eco-friendly process for production of chiral carbinols compared to chemical processes.
Iron(II)/(NH)2P2 Macrocycles: Modular, Highly Enantioselective Transfer Hydrogenation Catalysts
Bigler, Raphael,Huber, Raffael,St?ckli, Marco,Mezzetti, Antonio
, p. 6455 - 6464 (2016)
A generalized protocol for the synthesis of chiral (NH)2P2 macrocycles allows changing the linker between the phosphines and gives access to a family of such ligands, as demonstrated for the propane-1,3-diyl analogue. The corresponding complexes based on earth-abundant and nontoxic iron were applied as catalysts in the asymmetric transfer hydrogenation of polar double bonds. Thanks to the ligand modularity and to the use of tunable isonitriles as ancillary ligands, the catalyst system can be individually optimized for each substrate to give high enantioselectivity (up to 99.9% conversion and 99.6% ee, TOF up to >3950 h-1) for a broad scope of 26 substrates.
Asymmetric Transfer Hydrogenation of Ketones Using New Iron(II) (P-NH-N-P′) Catalysts: Changing the Steric and Electronic Properties at Phosphorus P′
Smith, Samantha A. M.,Prokopchuk, Demyan E.,Morris, Robert H.
, p. 1204 - 1215 (2017)
The asymmetric transfer hydrogenation (ATH) of ketones is an efficient method for producing enantio-enriched alcohols which are used as intermediates in a variety of industrial processes. Here we report the synthesis of new iron ATH precatalysts (S,S)-[FeBr(CO)(Ph2PCH2CH2NHCHPhCHPhNC=CHCH2PR′2)][BPh4] (R′=Et, and ortho-tolyl (o-Tol)) where one of the phosphine groups is modified with small alkyl and large aryl substituents to probe the effect of this change on the activity and selectivity of the catalytic system. A simple reversible equilibrium kinetic model is used to obtain the initial TOF and the inherent enantioselectivity S=kR/kS of these catalysts along with those for the previously reported catalysts with R′=Ph and Cy for the ATH of acetophenone. With an increase in the size of the PR′2 group, the TOF goes through a maximum at PPh2 while the S value goes through a maximum of 510 at R′=Cy. The complex with R′=o-Tol starts with a high S value of 200 but is rapidly changed to a second catalyst with an S value of 28. For the reduction of acetophenone to (R)-1-phenylethanol, turnover numbers of up to 5200 and ee up to 98 % were achieved. The chemotherapeutic pharmaceutical precursor (R)-(3′,5′-bis(trifluoromethyl))-1-phenylethanol is synthesized in up to 95 % ee. Several other alcohols can be prepared in greater than 90 % ee by choosing the precatalyst with the correctly matched steric properties. A hydride complex derived from the catalyst with R′=Cy is characterized by NMR spectroscopy. It is proposed that low concentration trans-hydride carbonyl complexes with the FeH parallel to the NH of the ligand are the active catalysts in all of these systems.
Asymmetric hydrogenation of benzalacetone catalyzed by TPPTS-stabilized Ru in ionic liquids
Wang, Jinbo,Qin, Ruixiang,Xiong, Wei,Liu, Derong,Feng, Jian
, p. 834 - 838 (2015)
Achiral monophosphine TPPTS [TPPTS: P(m-C6H4SO3Na)3]-stabilized Ru was successfully applied to catalyze the asymmetric hydrogenation of benzalacetone in ionic liquids using (S,S)-DPENDS [disodium salt of sulfonated (S,S)-1,2-diphenyl-1,2-ethylenediamine] as chiral modifier. Under the optimized reaction conditions, the conversion of benzalacetone, chemoselectivity, and enantioselectivity of 4-phenyl-3-buten-2-ol could be reached up to 99.5%, 98.8%, and 74.6%, respectively. The TPPTS-stabilized Ru catalyst immobilized in ionic liquids could be easily separated from the resulting products by extraction with n-hexane, which could be recycled and reused five times without significant loss in activity, chemoselectivity, and enantioselectivity.
Green and Recyclable Medium for Asymmetric Hydrogenation of Benzalacetone Catalyzed by RuCl2(TPPTS)2-(S,S)-DPENDS
Qin, Ruixiang,Wang, Jinbo,Xiong, Wei,Feng, Jian,Liu, Derong,Chen, Hua
, p. 1146 - 1153 (2012)
PEG400-H2O was a green and recyclable reaction medium for asymmetric hydrogenation of benzalacetone catalyzed by ruthenium achiral monophosphine complex, RuCl2(TPPTS)2 (TPPTS: P(m-C6H4SO3Na)3), which was modified by (S,S)-DPENDS (disodium salt of sulfonated (S,S)-1,2-diphenyl-1,2-ethylene-diamine). Under the optimized conditions, the chemoselectivity for 4-phenyl-3-buten-2-ol was 98.5% with a corresponding ee value of 74.3%. The resulting products could easily be separated from the catalyst by extraction with n-hexane. The catalyst immobilized on PEG400-H2O could be recycled and reused at least five times without significant loss of chemoselectivity and enantioselectivity.
Mechanistic implications of pseudo zero order kinetics in kinetic resolutions
Blackmond, Donna G.,Hodnett, Neil S.,Lloyd-Jones, Guy C.
, p. 7450 - 7451 (2006)
This work provides simulations as well as experimental results from kinetic resolutions to demonstrate that a constant product enantioselectivity versus conversion profile in kinetic resolution is not a general consequence of pseudo zero order kinetics in
An unsymmetrical iron catalyst for the asymmetric transfer hydrogenation of ketones
Smith, Samantha A.M.,Morris, Robert H.
, p. 1775 - 1779 (2015)
A new iron(II)(Ph2P-NH-N-PCy2) complex with a dicyclohexylphosphino group trans to the NH group was found to catalyze the asymmetric transfer hydrogenation of a variety of ketones with high enantioselectivity.
Kinetic Resolution of Unsymmetrical Acyclic Allyl Carbonates Using Trimethylsilyl Cyanide via Palladium-Catalyzed Asymmetric Allylic Alkylation
Bai, Da-Chang,Wang, Wan-Ying,Ding, Chang-Hua,Hou, Xue-Long
, p. 1510 - 1514 (2015)
The kinetic resolution of 1,3-disubstituted unsymmetrical allylic substrates with TMSCN as the nucleophile was realized via palladium-catalyzed asymmetric allylic alkylation, providing optically active allylic substrates and β,γ-unsaturated nitriles in good yield and enantioselectivity.
