402-63-1Relevant articles and documents
Dye-sensitized photo-hydrogenation of aromatic ketones on titanium dioxide under visible light irradiation
Kohtani, Shigeru,Nishioka, Saki,Yoshioka, Eito,Miyabe, Hideto
, p. 61 - 65 (2014)
Aromatic ketones were photocatalytically hydrogenated on P25 TiO 2 powder modified with metal free organic dyes under visible light irradiation. The suitable combination of dye-TiO2 and triethylamine as a sacrificial electron donor successfully extended the photocatalytic UV response of TiO2 toward visible light region in the photo-hydrogenation of acetophenone derivatives.
Pincerlike molybdenum complex and preparation method thereof, catalytic composition and application thereof, and alcohol preparation method
-
Paragraph 0125-0130, (2021/08/11)
The invention discloses a clamp-type molybdenum complex, a preparation method, a corresponding catalyst composition and application. The method comprises the steps: obtaining 9 molybdenum complexes with different structures through coordination reaction of 2-(substituent ethyl)-(5, 6, 7, 8-tetrahydroquinolyl) amine and a corresponding carbonyl molybdenum metal precursor; and catalyzing a ketone compound transfer hydrogenation reaction through a molybdenum complex to generate 40 alcohol compounds. The preparation method of the molybdenum complex is simple, high in yield and good in stability. For a transfer hydrogenation reaction of ketone, the molybdenum-based catalytic system has high catalytic activity and small molybdenum loading capacity, is used for production of aromatic and aliphatic alcohols, and has the advantages of simple method, small environmental pollution and high yield.
Manganese-catalyzed homogeneous hydrogenation of ketones and conjugate reduction of α,β-unsaturated carboxylic acid derivatives: A chemoselective, robust, and phosphine-free in situ-protocol
Topf, Christoph,Vielhaber, Thomas
, (2021/07/10)
We communicate a user-friendly and glove-box-free catalytic protocol for the manganese-catalyzed hydrogenation of ketones and conjugated C[dbnd]C[sbnd]bonds of esters and nitriles. The respective catalyst is readily assembled in situ from the privileged [Mn(CO)5Br] precursor and cheap 2-picolylamine. The catalytic transformations were performed in the presence of t-BuOK whereby the corresponding hydrogenation products were obtained in good to excellent yields. The described system offers a brisk and atom-efficient access to both secondary alcohols and saturated esters avoiding the use of oxygen-sensitive and expensive phosphine-based ligands.
Selective C-alkylation Between Alcohols Catalyzed by N-Heterocyclic Carbene Molybdenum
Liu, Jiahao,Li, Weikang,Li, Yinwu,Liu, Yan,Ke, Zhuofeng
supporting information, p. 3124 - 3128 (2021/09/20)
The first implementation of a molybdenum complex with an easily accessible bis-N-heterocyclic carbene ligand to catalyze β-alkylation of secondary alcohols via borrowing-hydrogen (BH) strategy using alcohols as alkylating agents is reported. Remarkably high activity, excellent selectivity, and broad substrate scope compatibility with advantages of catalyst usage low to 0.5 mol%, a catalytic amount of NaOH as the base, and H2O as the by-product are demonstrated in this green and step-economical protocol. Mechanistic studies indicate a plausible outer-sphere mechanism in which the alcohol dehydrogenation is the rate-determining step.
Postsynthetic Modification of Half-Sandwich Ruthenium Complexes by Mechanochemical Synthesis
Jia, Wei-Guo,Zhi, Xue-Ting,Li, Xiao-Dong,Zhou, Jun-Peng,Zhong, Rui,Yu, Haibo,Lee, Richmond
, p. 4313 - 4321 (2021/05/04)
A mild and environmentally friendly method to synthesize half-sandwich ruthenium complexes through the Wittig reaction between an aldehyde-tagged half-sandwich ruthenium complex and phosphorus ylide mechanochemically is reported herein. The mechanochemical synthesis of valuable half-sandwich ruthenium complexes resulted in a fast reaction, good yield with simple workup, and the avoidance of harsh reaction conditions and organic solvents. The synthesized half-sandwich ruthenium complexes exhibited high catalytic activity for transfer hydrogenation of ketones using 2-propanol as the hydrogen source and solvent. Density functional theory was carried out to propose a mechanism for the transfer hydrogenation process. The modeling suggests the importance of the labile p-cymene ligand in modulating the reactivity of the catalyst.
NHC ligand-based half-sandwich iridium complexes: synthesis, structure and catalytic activity in acceptorless dehydrogenation and transfer hydrogenation
Deng, Wei,Jin, Yan,Li, Rong-Jian,Liu, Zhen-Jiang,Wang, Yang,Yao, Zi-Jian
, p. 19002 - 19010 (2021/10/29)
A set of neutral C,C-chelate half-sandwich iridium(iii) complexes have been prepared with NHC ligands that contain pendant aromatic rings as potentially chelating donor sites. The catalytic activity of such iridium complexes has been investigated for the acceptorless dehydrogenation (AD) reactions of alcohols and for the transfer hydrogenation reactions of ketones. The prepared iridium(iii) complexes show excellent catalytic activity for AD reactions of a wide range of secondary alcohols, and they are also shown to be effective for the synthesis of aldehydes from primary alcohols without the observation of undesired byproducts such as esters. Additionally, these complexes are also highly efficient in transfer hydrogenation of ketones and aldehydes, which give the alcohols in good yields under mild conditions. The exact structure and bonding mode of the NHC-based iridium complexes was identified using various spectroscopic methods and single crystal X-ray analysis.
Transfer Hydrogenation of Ketones and Imines with Methanol under Base-Free Conditions Catalyzed by an Anionic Metal-Ligand Bifunctional Iridium Catalyst
Han, Xingyou,Li, Feng,Liu, Peng,Wang, Rongzhou,Xu, Jing
, p. 2242 - 2249 (2020/03/13)
An anionic iridium complex [Cp*Ir(2,2′-bpyO)(OH)][Na] was found to be a general and highly efficient catalyst for transfer hydrogenation of ketones and imines with methanol under base-free conditions. Readily reducible or labile substituents, such as nitro, cyano, and ester groups, were tolerated under present reaction conditions. Notably, this study exhibits the unique potential of anionic metal-ligand bifunctional iridium catalysts for transfer hydrogenation with methanol as a hydrogen source.
Assembled Multinuclear Ruthenium(II)-NNNN Complexes: Synthesis, Catalytic Properties, and DFT Calculations
Liu, Tingting,Wu, Kaikai,Wang, Liandi,Fan, Hongjun,Zhou, Yong-Gui,Yu, Zhengkun
, p. 93 - 104 (2019/12/30)
Using a coordinatively unsaturated 16-electron mononuclear ruthenium(II)-pyrazolyl-imidazolyl-pyridine complex [Ru(II)-NNN] as the building block and oligopyridines as the polydentate ligands, pincer-type tri- A nd hexanuclear ruthenium(II) complexes [Ru(II)-NNNN]n were efficiently assembled. These complexes were characterized by elemental analyses, NMR, IR, and MALDI-TOF mass spectroscopies. In refluxing 2-propanol, the multinuclear ruthenium(II)-NNNN complexes exhibited exceptionally high catalytic activity for the transfer hydrogenation of ketones at very low concentrations and reached turnover frequencies (TOFs) up to 7.1 × 106 h-1, featuring a remarkable cooperative effect from the multiple Ru(II)-NNNN functionalities. DFT calculations have revealed the origin of the high catalytic activities of these Ru(II)-NNNN complexes.
Ketone Hydrogenation by Using ZnO?Cu(OH)Cl/MCM-41 with a Splash of Water: An Environmentally Benign Approach
Choudhary, Neha,Ghosh, Topi,Mobin, Shaikh M.
, p. 1339 - 1348 (2020/03/23)
MCM-41-supported ZnO?Cu(OH)Cl nanoparticles were synthesized via an incipient wetness impregnation technique using zinc chloride and copper chloride salts as well as water at room temperature. The catalyst was characterized by powder X-ray diffraction (PXRD), infrared spectroscopy (IR), and TGA, whereas surface and morphological studies were performed by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The above studies revealed the incorporation of metal species into the pores of MCM-41, leading to a decrease in surface area of the nanoparticles that was found to be 239.079 m2/g. The substituents attached to the ketone determine the rate of the reaction, and the utilization of the green solvent ‘water’ astonishingly completes the hydrogenation reaction in 45 minutes at 40 °C with 100% conversion and 100% selectivity as analyzed by gas chromatography-mass spectrometry. Hence, ZnO?Cu(OH)Cl/MCM-41 nanoparticles with 2.46 wt% zinc and 6.39 wt% copper were demonstrated as an active catalyst for the reduction of ketones without using any gaseous hydrogen source making it highly efficient as well as environmentally and economically benign.
One-pot Chemoenzymatic Deracemisation of Secondary Alcohols Employing Variants of Galactose Oxidase and Transfer Hydrogenation
Yuan, Bo,Debecker, Damien P.,Wu, Xiaofeng,Xiao, Jianliang,Fei, Qiang,Turner, Nicholas J.
, p. 6191 - 6195 (2020/10/15)
Enantiomerically enriched chiral secondary alcohols serve as valuable building blocks for drug intermediates and fine chemicals. In this study the deracemisation of secondary alcohols to generate enantiomeric pure chiral alcohols has been achieved by combining enantio-selective enzymatic oxidation of a secondary alcohol, by a variant of GOase (GOase M3-5), with either non-selective ketone reduction via transfer hydrogenation (TH) or enantio-selective asymmetric transfer hydrogenation (ATH). Both the enzymatic oxidation system and the transition-metal mediated reduction system were optimised to ensure compatibility with each other resulting in a homogeneous reaction system. 1-(4-nitrophenyl)ethanol was generated with 99 % conversion and 98 % ee by the deracemisation method, and it has been extended to a series of other secondary alcohols with comparable results.
