1517-72-2Relevant articles and documents
Nickel Nanoparticles Supported on CMK-3 with Enhanced Catalytic Performance for Hydrogenation of Carbonyl Compounds
Kim, Daeho,Kang, Hyuntae,Park, Hyesu,Park, Sungkyun,Park, Ji Chan,Park, Kang Hyun
, p. 3469 - 3473 (2016)
Ordered mesoporous carbon materials are becoming increasingly important in catalysis applications due to their advantageous stability and surface properties. In this paper, we report a replication of the synthesis of mesoporous carbon CMK-3 using SBA-15 as a silica template. Ni/CMK-3 was prepared by incorporating Ni particles formed inside the pores of CMK-3 by impregnation of nickel nitrate and subsequent hydrogen reduction. The prepared Ni/CMK-3 has a large surface area and a very small nickel nanoparticle size (1 nm) with the aim of achieving high performance in catalytic hydrogenation reactions. Moreover, we demonstrate that CMK-3 has a higher stability than that of SBA-15 during the hydrogenation reactions of acetophenone derivatives.
Malek,Cerny
, p. 53 (1973)
Ferrocene-based aminophosphine ligands in the Ru(II)-catalysed asymmetric hydrogenation of ketones: assessment of the relative importance of planar versus carbon-centred chirality
Chen, Weiping,Mbafor, William,Roberts, Stanley M.,Whittall, John
, p. 1161 - 1164 (2006)
Several ferrocene-based aminophosphine ligands have been prepared and shown to be effective in the Ru(II)-catalysed asymmetric hydrogenation of ketones. The enantioselectivity is mainly determined by the carbon-centred chirality of the ligands but the planar chirality is also important such that (RC,SFc)- or (SC,RFc)- are the matched chiralities.
Synthesis and enantiomeric resolution of medetomidine
Fakhraian,Toulabi,Choobdari,Peyrovi,Ghanbary, H. Hadj
, p. 141 - 148 (2015)
Medetomidine {4-[l-(2,3-dimethylphenyl)ethyl]-3H-imidazole], 5} is a selective α2-adrenoceptor agonist used in veterinary medicine for its analgesic and sedative properties. It is also an alternative and environmentally acceptable anti-fouling biocide which impedes the settlement of barnacles at nanomolar concentrations and replaces toxic antifouling coatings based on heavy metals. Several syntheses of medetomidine have been reported. The first method for the preparation of 5 and of other related 4-benzylimidazoles was described in a patent starting from 2,3-dimethylbromobenzene as shown in Scheme 1; unfortunately the yields were not reported.
Design of boron bis-oxazolinate (B-BOXate) complexes: A new class of stable organometallic catalysts
Bandini,Cozzi,Monari,Perciaccante,Selva,Umani-Ronchi
, p. 1318 - 1319 (2001)
A new class of remarkably stable B-BOXate complexes has been synthesised, isolated and employed as chiral catalysts for asymmetric reduction of variously substituted prochiral ketones.
Synthesis of Ru-coordinating helical polymer and its utilization as a catalyst for asymmetric hydrogen-transfer reaction
Sanda, Fumio,Araki, Hitoshi,Masuda, Toshio
, p. 1642 - 1643 (2005)
An L-threonine-based helical poly(N-propargylamide)-Ru complex was synthesized, and used as a catalyst for hydrogen-transfer reaction of ketones. The enantiomeric excess (ee) values of the formed alcohols ranged from 12 to 36%. On the other hand, an Ru complex with a low-molecular-weight model ligand gave an alcohol with ee as low as 1.8%. Copyright
One-pot synthesis of (R)-1-(1-naphthyl)ethanol by stereoinversion using Candida parapsilosis
Amrutkar, Suyog Madhav,Banoth, Linga,Banerjee, Uttam Chand
, p. 3274 - 3277 (2013)
(R)-1-(1-Naphthyl)ethanol is an essential chiral substrate for the synthesis of nonactin and dihydro-[1H]-quinoline-2-one derivatives. Stereoinversion of (S)-1-(1-naphthyl)ethanol to (R)-1-(1-naphthyl)ethanol by whole cell biocatalysis, using Candida parapsilosis, is reported here. Candida parapsilosis possesses a requisite redox system for the stereoinversion of secondary alcohol. The reaction conditions (temperature, time, pH, organic solvent, etc.) significantly influenced the stereoinversion process. Optimum conditions were found to be the reaction temperature of 30 C, a cellmass concentration of 200 mg/mL, pH 7 (phosphate buffer, 50 mM), a shaking speed of 200 rpm, and a 12 h reaction time. Under these optimum conditions, (R)-1-(1-naphthyl)ethanol was obtained in 100% eeR and 88% yield.
A Simple Method for enriching the Enantiomeric Purity of a Functional Molecule already Rich in One Enantiomer
Fleming, Ian,Ghosh, Sunil K.
, p. 99 - 100 (1994)
1-Naphth-1-ylethanol 1 of 92percent enantiomeric excess (e.e.) can be raised to 99.6percent e.e. in an overall yield of 78percent by attaching it to oxalyl chloride, separating the lk diester from the ul by crystallisation, and hydrolysing the diester; the method is potentially general for functional molecules that can easily be attached to and then taken off a bifunctional reagent.
Reducing ability of supramolecular C60 dianion toward C=O, C=C and N-N bonds
Takekuma, Shin-Ichi,Takekuma, Hideko,Yoshida, Zen-Ichi
, p. 1628 - 1630 (2005)
Different from C60 dianion which readily reacts with electrophiles, supramolecular C60 dianion (2) generated from γ-cyclodextrin-bicapped C60 (1) and NaBH4 (or diborate) in DMSO-H2O (9:1, v/v) is able to reduce N-N+, C=C-EWG and C=O bonds to provide the respective dihydro derivatives; 1-mediated reduction of acetophenone with NaBH4 in the presence of (Me 2N)2CH2 and EtONa gives turn over frequency (TOF)/h of 400. The Royal Society of Chemistry 2005.
Chiral Recognition and Molecular Interaction in Cellulose Derivatives
Itoh, Kenji,Ikeda, Tomiki,Tazuke, Shigeo,Shibata, Tohru
, p. 5759 - 5765 (1992)
Nineteen 1,3-bis(aryl)propane derivatives and six model compounds with a single chromophore were used to explore the chiral discrimination ability of cellulose derivatives, in particular cellulose triphenylcarbamate (CTC), in connection with the mode of interaction of these probe molecules with adsorbents.The interaction was evaluated by conformational analysis of the probe molecules and circular dichroism.The 1,3-bis(aryl)propanes with 9-anthryl moieties possessed a highly limited conformation owing to the bulky substituent and hardly changed their shape on CTCas evidenced by CD spectra; thus, they may be regarded as "rigid" substrates.However, these "rigid" substrates were resolved quite effectively.On the other hand, those with 2-naphthyl moieties possessed a number of stable conformations and could change their shape in diastereomeric complexes on CTC; thus, they may be assumed as "soft" substrates, against which the chiral discrimination was inefficient.The present study revealed that the optical resolution may be interpreted at least partly in terms of the "rigid" and "soft" concept.
Synthesis of a rhodium(III) triphenylphosphine complex via C–S bond cleavage of an azo-thioether ligand: X-ray structure, electrochemistry and catalysis towards transfer hydrogenation of ketones
Roy, Puspendu,Manna, Chandan Kumar,Naskar, Rahul,Mondal, Tapan Kumar
, p. 208 - 214 (2019)
A new rhodium(III) triphenylphosphine complex having the general formula [Rh(PPh3)2(L)Cl] (1) was synthesized by C–S bond cleavage of an ONS donor azo-thioether ligand (L-CH2Ph). The complex was thoroughly characterized by various spectroscopic techniques. Its single crystal X-ray structure exhibits an octahedral geometry around the rhodium(III) center. A cyclic voltammogram of the complex exhibits ligand based quasi-irreversible oxidative and reductive responses. The electronic structure, redox properties and electronic excitations in the complex were interpreted by DFT and TDDFT calculations. The complex effectively catalyzed the transfer hydrogenation reaction of ketones with high yields in i-PrOH in the presence of a base.
A cyclochiral conformational motif constructed using a robust hydrogen-bonding network
Mishiro, Kenji,Furuta, Takumi,Sasamori, Takahiro,Hayashi, Kazuhiro,Tokitoh, Norihiro,Futaki, Shiroh,Kawabata, Takeo
, p. 13644 - 13647 (2013)
A novel conformational motif constructed with a robust intramolecular hydrogen-bonding (H-bonding) network was discovered. A pyrrolidine derivative possessing four identical amide substituents at C(2) and C(5) formed a strong intramolecular H-bonding network consisting of all the amide groups. This conformation yielded a cyclochiral structure with a handedness that depended on the directionality of the H-bonding network. The most stable compound was isolated and applied to the acylative kinetic resolution of secondary alcohol. The handedness of the H-bonding network was biased by the presence of chiral substituents, and the preferred direction could be switched under an external stimulus. A structural analysis using NMR, X-ray crystallography, and theoretical calculation techniques indicated that the conformation of the substituents was highly ordered and depended on the directionality of the H-bonding network.
Applications of imino-pyridine Ni(II) complexes as catalysts in the transfer hydrogenation of ketones
Tsaulwayo, Nokwanda,Kumah, Robert.T.,Ojwach, Stephen.O.
, (2021)
Five imino-pyridine Ni(II) complexes: [{Ni(L1)Cl2}2] Ni1; [{Ni(L2)Cl2}2] Ni2; [{Ni(L3)Cl2}2] Ni3; [{Ni(L4)Cl2}2] Ni4 and [Ni(L5)2Cl2] Ni5 derived from ligands 2,6-diisopropyl-N-[(pyridin-2-yl) methylene] aniline (L1); 2,6-diisopropyl-N-[(pyridin-2-yl) ethylidene]aniline (L2); 2,6-dimethyl-N-[(pyridin-2-yl) methylene] aniline (L3); 2,6-dimethyl-N-[(pyridin-2-yl) ethylidene] aniline (L4) and N-[(pyridin-2-yl) methylene] aniline (L5) were evaluated as catalysts in the transfer hydrogenation of ketones. The Ni(II) complexes demonstrated moderate catalytic activities giving a turnover number (TON) of up to 126 at catalyst loading of 0.5 mol%. The structure of the complexes and nature of ketone substrate influenced the catalytic activities of the complexes. Deactivation studies using mercury and sub-stoichiometric poisoning experiments pointed to the presence of both Ni(0) nanoparticles and Ni(II) homogeneous as the active species.
Functional-group attachment and interconversion at a chiral [3]ferrocenophane framework
Nilewski, Christian,Neumann, Markus,Tebben, Ludger,Froehlich, Roland,Kehr, Gerald,Erker, Gerhard
, p. 2191 - 2200 (2006)
Mannich condensation of 1,1′-diacetylferrocene with dimethylamine followed by catalytic hydrogenation gives the chiral α-dimethylamino[3] ferrocenophane. Both enantiomers are available by resolution. Directed ortho-lithiation/iodination yields the ]ortho-iodo-α-dimethylamino[3] ferrocenophane derivative, whose treatment with acetic anhydride and copper(I) oxide yielded the mono- and diacetoxy-functionalized derivatives. The ortho-phosphorylated α-dimethylamino systems (-PPh2, -PCy 2) underwent exchange of the directing NMe2 group with NH2 by means of an ammonolysis reaction of the corresponding α-chloride derivatives, which in turn were obtained by treatment of the α-dimethylamino compounds with methylchloroformate. Starting from α-dimethylamino[3]ferrocenophane, the sequence of directed ortho-lithiation (t-BuLi), treatment with p-tosyl azide/sodium pyrophosphate (to yield the ortho-azido[3]ferrocenophane derivative) followed by catalytic hydrogenation gave the ortho-amino and α-dimethylamino[3]ferrocenophane derivatives. The potential use of some of the chelate ferrocenophane ligands in Ru-catalyzed asymmetric hydrogenations was investigated. Seven of the newly synthesized compounds were characterized by X-ray diffraction. Georg Thieme Verlag Stuttgart.
Synthesis and characterization of a ruthenium complex with bis(diphenylphosphino)propane and thioether containing ONS donor ligand: Application in transfer hydrogenation of ketones
Biswas, Sujan,Sarkar, Deblina,Roy, Puspendu,Mondal, Tapan Kumar
, p. 1 - 7 (2017)
The synthesis and characterization of a mixed ligand Ru(II) complex, [Ru(dppp)(L)Cl] (1) (where, dppp?=?bis(diphenylphosphino) propane) is reported. The distorted octahedral geometry of the complex is confirmed by X-ray diffraction method. Cyclic voltammogram in CH3CN exhibits Ru(II)/Ru(III) quasireversible oxidation couple along with reversible azo-bond reductions peaks with reference to Ag/AgCl electrode. The efficiency of the complex towards the transfer hydrogenation of ketones in i-PrOH is examined and an excellent catalytic conversion (90–98%) is observed. The electronic structure and redox properties are well corroborated with the DFT calculations.
Asymmetric hydrogenation of aromatic ketones using polymeric catalyst prepared from polymer-supported 1,2-diamine
Itsuno, Shinichi,Chiba, Masahiro,Takahashi, Miyuki,Arakawa, Yukihiro,Haraguchi, Naoki
, p. 487 - 494 (2007)
tert-Butyloxycarbonyl (Boc) protected chiral 1,2-diamine monomers 3 were copolymerized with achiral vinyl monomers such as styrene, methacrylates, acrylates, methacrylamide, and acrylamide to give crosslinked polymers P2 containing chiral 1,2-diamine moie
Axial chirality in biaryl N,N-dialkylaminopyridine derivatives bearing an internal carboxy group
Nishino, Reiko,Hamada, Shohei,Elboray, Elghareeb E.,Ueda, Yoshihiro,Kawabata, Takeo,Furuta, Takumi
, p. 588 - 593 (2020)
Axial chirality in N,N-dimethylaminopyridines as well as N,N-dipropylaminopyridines bearing an internal carboxy group were evaluated based on their racemization barriers and circular dichroism spectra. The half-life of racemization of N,N-dipropylaminopyridine derivative 2 was estimated to be 19.7 days at 20°C. Its enantiomers isolated as optically active forms showed positive-negative and negative-positive Cotton effects for (+)-2 and (?)-2, respectively, from 310 to 210 nm. Furthermore, (?)-2 was applied as a chiral nucleophilic catalyst and exhibited asymmetric induction in acylative kinetic resolution of 1-(1-naphthyl)ethane-1-ol.
Parallel kinetic resolution
Vedejs,Chen
, p. 2584 - 2585 (1997)
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An efficient phosphorous-containing oxazoline ligand derived from cis-2-amino-3,3-dimethyl-1-indanol: Application to the rhodium-catalyzed enantioselective hydrosilylation of ketones
Sudo, Atsushi,Yoshida, Hiroaki,Saigo, Kazuhiko
, p. 3205 - 3208 (1997)
Enantiopure 2-[2-(diphenylphosphino)phenyl]oxazoline, derived from a non-natural amino alcohol, cis-2-amino-3,3-dimethyl-1-indanol, was found to be an efficient ligand for the rhodium-catalyzed enantioselective hydrosilylation of ketones.
Effectiveness and Mechanism of the Ene(amido) Group in Activating Iron for the Catalytic Asymmetric Transfer Hydrogenation of Ketones
Xue, Qingquan,Wu, Rongliang,Wang, Di,Zhu, Meifang,Zuo, Weiwei
supporting information, p. 134 - 147 (2021/02/05)
I-interacting ligands of the diphosphino amido-ene(amido) type are effective in activating iron to resemble the properties of precious metals in the catalytic asymmetric transfer hydrogenation of ketones. To further verify the effectiveness of the ene(amido) group, we synthesized four amine(imine) diphosphine iron precatalyst complexes with substituents at α and β positions relative to imino groups (1-3) or with enlarged chelate ring sizes (5,5,6-membered rings) (4). In comparison with the parent trans-(R,R)-[Fe(CO)(Cl)(PPh2CH2CHaNCHPhCHPhNHCH2CH2PPh2)]BF4 (I), the introduction of a methyl group in 1 and 2 reduced the catalytic activity but led to undiminished enantioselectivity as reaction proceeded. In comparison to the iron complexes 1-3 with a 5,5,5-coordination geometry, the complex 4 derived from the new (R,R)-P-NH-NH2 tridentate ligand showed high reactivity comparable to that of I but was unfortunately not enantioselective. The catalytic reactivity of 1, 2, and 4 illustrates the effectiveness of the ene(amido) group. An electronic structure study on the important catalytic intermediate amido-ene(amido) complex 1b proved that iron was activated by an additional I-back-donation-interaction ligand to participate in the traditional metal-ligand bifunctional pathway in the asymmetric transfer hydrogenation reactions.
Dynamic Kinetic Resolution of Alcohols by Enantioselective Silylation Enabled by Two Orthogonal Transition-Metal Catalysts
Oestreich, Martin,Seliger, Jan
, p. 247 - 251 (2020/10/29)
A nonenzymatic dynamic kinetic resolution of acyclic and cyclic benzylic alcohols is reported. The approach merges rapid transition-metal-catalyzed alcohol racemization and enantioselective Cu-H-catalyzed dehydrogenative Si-O coupling of alcohols and hydrosilanes. The catalytic processes are orthogonal, and the racemization catalyst does not promote any background reactions such as the racemization of the silyl ether and its unselective formation. Often-used ruthenium half-sandwich complexes are not suitable but a bifunctional ruthenium pincer complex perfectly fulfills this purpose. By this, enantioselective silylation of racemic alcohol mixtures is achieved in high yields and with good levels of enantioselection.
Tridentate nitrogen phosphine ligand containing arylamine NH as well as preparation method and application thereof
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Paragraph 0095-0102; 0105-0109, (2021/06/26)
The invention discloses a tridentate nitrogen phosphine ligand containing arylamine NH as well as a preparation method and application thereof, and belongs to the technical field of organic synthesis. The tridentate nitrogen phosphine ligand disclosed by the invention is the first case of tridentate nitrogen phosphine ligand containing not only a quinoline amine structure but also chiral ferrocene at present, a noble metal complex of the type of ligand shows good selectivity and extremely high catalytic activity in an asymmetric hydrogenation reaction, meanwhile, a cheap metal complex of the ligand can also show good selectivity and catalytic activity in the asymmetric hydrogenation reaction, and is very easy to modify in the aspects of electronic effect and space structure, so that the ligand has huge potential application value. A catalyst formed by the ligand and a transition metal complex can be used for catalyzing various reactions, can be used for synthesizing various drugs, and has important industrial application value.
