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UNUSUAL HIGH REACTIVITIES OF 5α- AND 5β-CHOLESTAN-3-ONES IN THE HYDROGENATION CATALYZED BY PALLADIUM. EVIDENCE FOR AN ATTRACTIVE INTERACTION OF THE STEROID α-FACE WITH PALLADIUM
5α- And 5β-cholestan-3-ones are 30 and 17 times as reactive as 4-t-butylcyclohexanone in Pd catalyzed competitive hydrogenation in t-BuOH.The high reactivity of the steroid ketones and unusual hydrogenation stereochemistry on Pd have been explained on the basis of an attractive interaction of the steroid α-face with Pd.
Nishimura, Shigeo,Murai, Mikio,Shiota, Michio
p. 1239 - 1242
(1980)
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SOMC?Periodic Mesoporous Silica Nanoparticles: Meerwein-Ponndorf-Verley Reduction Promoted by Immobilized Rare-Earth-Metal Alkoxides
The Meerwein-Ponndorf-Verley (MPV) reduction is a reaction that offers a mild reduction of aldehydes and ketones to the corresponding alcohols. Although described as a catalytic reaction, its real-life applicability suffers from the necessity of using the standard catalyst [Al(OiPr)3] in stoichiometric amounts or even in excess. Rare-earth-metal-based catalysts are capable of performing in these reactions in a truly catalytic fashion. The ceric alkoxide [Ce(OiPr)4]3 has been synthesized via silylamine elimination from Ce[N(SiHMe2)2]4 with isopropyl alcohol, its trimetallic solid-state structure has been determined by X-ray diffraction, and its performance in the MPV reduction of 4-tBu-cyclohexanone has been examined and compared to that of cerous [Ce(OCH2tBu)3]4. Spherical mesoporous silica nanoparticles with an MCM-41-type honeycomb pore symmetry, termed MSN-MCM-41 (particle size, ca. 250 nm diameter; pore size, 2.6 nm diameter), are employed for grafting the molecular precursors Ce[N(SiHMe2)2]4, [Ce(OiPr)4]3, Ce[N(SiMe3)2]3, and La[N(SiMe3)2]3 according to the methods of surface organometallic chemistry (SOMC). The MPV reductions carried out with the homogeneous and heterogeneous catalysts reveal (a) a better performance of Ce(III) in comparison to Ce(IV), (b) better performance of La[N(SiMe3)2]3?MSN-MCM-41 in comparison to Ce[N(SiMe3)2]3?MSN-MCM-41 (high sensitivity of Ce(III)-grafted materials), and (c) reusability of the grafted catalyst systems. All hybrid materials were characterized by PXRD, N2 physisorption, and 1H/13C/29Si MAS NMR and FTIR spectroscopies as well as elemental analysis.
Anwander, Reiner,Bock, Lorenz,Kramer, Markus,Liang, Yucang,Maichle-M?ssmer, C?cilia,Tran, Xuan
p. 1046 - 1058
(2020)
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A direct conversion of aldohexopyranose to ketohexopyranose benzyl derivatives by Meerwein-Ponndorf/Oppenauer reaction induced by air-oxidised samarium diiodide
2,3,4,6-tetra-O-benzyl-D-galactopyranose and 2,3,4,6-tetra-O-benzyl-D-glucopyranose can be reduced at C-1 and oxidised at C-5 to give 1,3,4,5-tetra-O-benzyl-L-tagatopyranose and 1,3,4,5-tetra-O-benzyl-L-sorbopyranose, respectively, in good yields, through an intramolecular M-P/O reaction induced by preoxidised samarium diiodide.
Adinolfi, Matteo,Iadonisi, Alfonso,Mangoni, Lorenzo
p. 5987 - 5988
(1996)
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Aromatic compound hydrogenation and hydrodeoxygenation method and application thereof
The invention belongs to the technical field of medicines, and discloses an aromatic compound hydrogenation and hydrodeoxygenation method under mild conditions and application of the method in hydrogenation and hydrodeoxygenation reactions of the aromatic compounds and related mixtures. Specifically, the method comprises the following steps: contacting the aromatic compound or a mixture containing the aromatic compound with a catalyst and hydrogen with proper pressure in a solvent under a proper temperature condition, and reacting the hydrogen, the solvent and the aromatic compound under the action of the catalyst to obtain a corresponding hydrogenation product or/and a hydrodeoxygenation product without an oxygen-containing substituent group. The invention also discloses specific implementation conditions of the method and an aromatic compound structure type applicable to the method. The hydrogenation and hydrodeoxygenation reaction method used in the invention has the advantages of mild reaction conditions, high hydrodeoxygenation efficiency, wide substrate applicability, convenient post-treatment, and good laboratory and industrial application prospects.
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Paragraph 0094-0096; 0098; 0100-0104

(2021/05/29)

Half-sandwich rhodium complexes with phenylene-based SCS ligands: Synthesis, characterization and catalytic activities for transfer hydrogenation of ketones
A series of half-sandwich rhodium complexes with tridentate phenylene-based bis(thione) (SCS) ligand have been synthesized and characterized. Both half-sandwich rhodium complexes and phenylene-based bis(thione) compounds were fully characterized by 1H and 13C NMR spectra, mass spectrometry and single-crystal X-ray diffraction method. The catalytic activities of half-sandwich rhodium complexes toward the transfer hydrogenation of ketones to their corresponding alcohols were explored using 2-propanol as hydrogen source and solvent. And the half-sandwich rhodium complexes exhibited high catalytic activity for transfer hydrogenation of ketones with a broad functional group tolerance.
Jia, Wei-Guo,Gao, Li-Li,Zhi, Xue-Ting,Li, Xiao-Dong,Wang, Zhi-Bao,Sun, Ying
(2020/12/30)

Postsynthetic Modification of Half-Sandwich Ruthenium Complexes by Mechanochemical Synthesis
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.
Jia, Wei-Guo,Zhi, Xue-Ting,Li, Xiao-Dong,Zhou, Jun-Peng,Zhong, Rui,Yu, Haibo,Lee, Richmond
p. 4313 - 4321
(2021/05/04)

Base-free transfer hydrogenation of aryl-ketones, alkyl-ketones and alkenones catalyzed by an IrIIICp* complex bearing a triazenide ligand functionalized with pyrazole
An IrIIICp* complex (2) bearing a triazenide ligand functionalized with pyrazole was synthesized and fully characterized by spectroscopic methods and the structure confirmed by X-ray diffraction studies. The catalytic activity of 2 and the control complex 3, which lacks of pyrazole in its structure, was evaluated in the reduction of aryl-ketones, alkyl-ketones, α,β-unsaturated and γ,δ-unsaturated ketones. The catalytic system, using either 2 or 3, exhibited good to excellent selectivity when tested with ketones and alkenones at 90 °C in 2-propanol as hydrogen source under base-free conditions. Reactivity of 2 in 2-propanol and NaH gave a neutral metal hydride (4) while in the absence of base gave two major cationic hydrides species (5 and 6).
Medrano-Castillo, Layla J.,Collazo-Flores, Miguel á.,Camarena-Díaz, Juan P.,Correa-Ayala, Erick,Chávez, Daniel,Grotjahn, Douglas B.,Rheingold, Arnold L.,Miranda-Soto, Valentín,Parra-Hake, Miguel
(2020/03/13)

Synthesis and characterization of silica-coated magnetite nanoparticles modified with bis(pyrazolyl) triazine ruthenium(II) complex and the application of these nanoparticles as a highly efficient catalyst for the hydrogen transfer reduction of ketones
We present a facile and efficient method for modifying the surface of silica-coated Fe3O4 magnetic nanoparticles (MNPs) with bis(pyrazolyl) triazine ruthenium(II) complex [MNPs@BPT–Ru (II)]. Field emission-scanning electron microscopy, thermogravimetric/derivative thermogravimetry analysis, X-ray powder diffraction, Fourier-transform infrared spectroscopy, vibrating sample magnetometry, and energy-dispersive X-ray spectrometry analyses were employed for characterizing the structure of these nanoparticles. MNPs@BPT–Ru(II) nanoparticles proved to be a magnetic, reusable, and heterogeneous catalyst for the hydrogen transfer reduction of ketone derivatives. In addition, highly pure products were obtained with excellent yields in relatively short times in the presence of this catalyst. A comparison of this catalyst with those previously used for the hydrogen transfer reactions proved the uniqueness of MNPs@BPT–Ru(II) nanoparticle which is due to its inherent magnetic properties and large surface area. The presented method also had other advantages such as simple reaction conditions, eco-friendliness, high recovery ability, easy work-up, and low cost.
Mobinikhaledi, Akbar,Moghanian, Hassan,Ajerloo, Bahram,Dousti, Fatemeh
(2019/12/24)

Selective phenol hydrogenation under mild condition over Pd catalysts supported on Al2O3 and SiO2
Cyclohexanone (CHONE) is the key intermediate in the manufacture of nylon-6 and nylon-66. Selective hydrogenation of phenol into CHONE was investigated over Pd/SiO2 and Pd/Al2O3. The results show that the yield of CHONE reaches 98% or more over Pd/Al2O3 and Pd/SiO2 at 333?K under atmospheric pressure in cyclohexane solvent. High activity of Pd/Al2O3 is promoted by Lewis acidity, and phenol can be converted 100% within 300?min. The hydrogenation of CHONE occurs until the conversion of phenol approaches completion. Pd/SiO2 with smaller Pd nano-particles presents higher selectivity. For polar solvent, such as ethanol and dichloromethane, the activity of Pd catalysts decreases greatly. Auxiliary experiments verify that phenol adsorbs on Pd catalysts via the formation of π–c with an aromatic ring. Increased hydrogen pressure not only promotes significantly the rates of hydrogenation, but also increases the selectivity for CHONE, especially over Pd/SiO2-1 catalyst.
Li, Xinzheng,Cheng, Ling,Wang, Xingyi
p. 1249 - 1262
(2019/02/24)

A Practical and Stereoselective In Situ NHC-Cobalt Catalytic System for Hydrogenation of Ketones and Aldehydes
Homogeneous catalytic hydrogenation of carbonyl groups is a synthetically useful and widely applied organic transformation. Sustainable chemistry goals require replacing conventional noble transition metal catalysts for hydrogenation by earth-abundant base metals. Herein, we report how a practical in situ catalytic system generated by easily available pincer NHC precursors, CoCl2, and a base enabled efficient and high-yielding hydrogenation of a broad range of ketones and aldehydes (over 50 examples and a maximum turnover number [TON] of 2,610). This is the first example of NHC-Co-catalyzed hydrogenation of C=O bonds using flexible pincer NHC ligands consisting of a N-H substructure. Diastereodivergent hydrogenation of substituted cyclohexanone derivatives was also realized by fine-tuning of the steric bulk of pincer NHC ligands. Additionally, a bis(NHCs)-Co complex was successfully isolated and fully characterized, and it exhibits excellent catalytic activity that equals that of the in-situ-formed catalytic system. Catalytic hydrogenation is a powerful tool for the reduction of organic compounds in both fine and bulk chemical industries. To improve sustainability, more ecofriendly, inexpensive, and earth-abundant base metals should be employed to replace the precious metals that currently dominate the development of hydrogenation catalysts. However, the majority of the base-metal catalysts that have been reported involve expensive, complex, and often air- and moisture-sensitive phosphine ligands, impeding their widespread application. From a mixture of the stable CoCl2, imidazole salts, and a base, our newly developed catalytic system that formed easily in situ enables efficient and stereoselective hydrogenation of C=O bonds. We anticipate that this easily accessible catalytic system will create opportunities for the design of practical base-metal hydrogenation catalysts. A practical in situ catalytic system generated by a mixture of easily available pincer NHC precursors, CoCl2, and a base enabled highly efficient hydrogenation of a broad range of ketones and aldehydes (over 50 examples and up to a turnover number [TON] of 2,610). Diastereodivergent hydrogenation of substituted cyclohexanone derivatives was also realized in high selectivities. Moreover, the preparation of a well-defined bis(NHCs)-Co complex via this pincer NHC ligand consisting of a N-H substructure was successful, and it exhibits equally excellent catalytic activity for the hydrogenation of C=O bonds.
Zhong, Rui,Wei, Zeyuan,Zhang, Wei,Liu, Shun,Liu, Qiang
supporting information
p. 1552 - 1566
(2019/06/14)

Preparation and spectroscopic studies of Fe(II), Ru(II), Pd(II) and Zn(II) complexes of Schiff base containing terephthalaldehyde and their transfer hydrogenation and Suzuki-Miyaura coupling reaction
This study describes synthesis, spectroscopic characterization and catalytic activities of Fe(II), Ru(II), Pd(II) and Zn(II) complexes with a novel Schiff base ligand (L) derived from methyl 2-amino-5,5,7,7-tetramethyl-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylate and terephthalaldehyde. We used spectroscopic techniques including IR, UV-Vis, 1H-NMR, 13C-NMR, elemental analysis and also mass analysis and magnetic susceptibility measurements to identify the products. The Pd(II) complex was used as a potential catalyst for Suzuki-Miyaura coupling reaction of some aryl halides under optimized conditions. The effect of various bases such as NaOH, KOH, and KOBut was investigated in transfer hydrogenation (TH) of ketones by isopropyl alcohol as the hydrogen source. Ru(II) and Pd(II) complexes showed catalytic activity while Zn(II) and Fe(II) metal complexes failed to do that.
Turan, Nevin,Buldurun, Kenan,?olak, Naki,?zdemir, ?°smail
p. 571 - 580
(2019/10/21)

Production method of iris ester synthetic essence
The invention discloses a production method of an iris ester synthetic essence, which relates to the technical field of fine chemical production. The phenol and tert-butyl alcohol are taken as initialraw materials for an alkylation reaction, after hydrogenation, the materials and acetic anhydride are subjected to an acetylation reaction to generate iris ester, the raw materials are easily available, and yield is high; petroleum ether is taken as an organic solvent of the alkylation reaction and a hydrogenation reaction, the disadvantages that the reaction is incomplete during a hydrogenationprocess and a catalyst is inactivated after application can be overcome, and a distillation technology step employed in the alkylation reaction by employing dichloroethane as a solvent is simultaneously omitted; a boiling point of petroleum ether is low, and the petroleum ether is easily recovered and applied, so that environment pollution due to discharge of the organic solvent in waste water canbe avoided, and production cost is reduced.
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(2018/05/03)

Production method of tertiary butyl cylcohexyl ethyl carbonate synthetic perfume
The invention discloses a production method of a tertiary butyl cylcohexyl ethyl carbonate synthetic perfume and relates to the technical field of fine chemical production. The production method provided by the invention comprises the following steps of by taking phenol and tert-butyl alcohol as starting materials to perform alkylation reaction, then performing hydrogenation on a reactant, and performing acetylation reaction on the reactant and diethyl carbonate to produce tertiary butyl cylcohexyl ethyl carbonate, wherein the raw materials are available, the yield is high, the proportion of o-tert butylphenol produced by reaction of the phenol and the tert-butyl alcohol and p-tert-butylphenol reaches 7 to 3, an iris ester product can be obtained after performing hydrogenation and esterification on the p-tert-butylphenol as a by-product and is put to use. The production method is strong in controllability of technological parameters, good in repeatability and simplified in operation; and a product is high in purity, pure and gentle in fragrance and accords with the flavor blending requirements for an essence perfume.
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Paragraph 0041-0051

(2018/03/24)

Synthesis method of o-tert-butyl cyclohexyl acetate essence
The invention discloses a synthesis method of o-tert-butyl cyclohexyl acetate essence, which includes the following steps: a) successively adding petroleum ether and phenol to a three-neck glass flask, and adding TiO2-supported phosphotungstic acid catalyst, dropwise adding tert-butyl alcohol at 10 - -15 DEG C, and layering a reaction liquid mixture, generated in the glass flask, of o-tert-butyl phenol and p-tert-butyl phenol; b) washing an oil layer successively with alkali and water, and performing a hydrogenation reaction under a Pd/C catalyst, collecting o-tert-butyl cyclohexanol, adding acetic anhydride and p-toluenesulfonic acid, recovering the acetic acid, and alkali-washing, water-washing and evaporating the oil layer to prepare the o-tert-butyl cyclohexyl acetate essence. The method employs easy-to-obtained raw materials and is high in yield, wherein final product content can reach more than 98.5% and content of cis-isomers in the product can reach more than 85%. The ssence has a pure and mellow fragrance and satisfies the demand of essence and perfumes in flavor blending.
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Paragraph 0012; 0013; 0014

(2018/04/26)

Ductile Pd-Catalysed Hydrodearomatization of Phenol-Containing Bio-Oils Into Either Ketones or Alcohols using PMHS and H2O as Hydrogen Source
A series of phenolic bio-oil components were selectively hydrodearomatized by palladium on carbon into the corresponding ketones or alcohols in excellent yields using polymethylhydrosiloxane and water as reducing agent. The selectivity of the reaction was governed by the water concentration where selectivity to alcohol was favoured at higher water concentrations. As phenolic bio-oil examples cardanol and beech wood tar creosote were studied as substrate to the developed reaction conditions. Cardanol was hydrodearomatized into 3-pentadecylcyclohexanone in excellent yield. From beech wood tar creosote, a mixture of cyclohexanols was produced. No hydrodeoxygenation occurred, suggesting the applicability of the reported method for the production of ketone-alcohol oil from biomass. (Figure presented.).
Di Francesco, Davide,Subbotina, Elena,Rautiainen, Sari,Samec, Joseph S. M.
supporting information
p. 3924 - 3929
(2018/09/14)

Creating Hierarchical Pores by Controlled Linker Thermolysis in Multivariate Metal-Organic Frameworks
Sufficient pore size, appropriate stability, and hierarchical porosity are three prerequisites for open frameworks designed for drug delivery, enzyme immobilization, and catalysis involving large molecules. Herein, we report a powerful and general strategy, linker thermolysis, to construct ultrastable hierarchically porous metal-organic frameworks (HP-MOFs) with tunable pore size distribution. Linker instability, usually an undesirable trait of MOFs, was exploited to create mesopores by generating crystal defects throughout a microporous MOF crystal via thermolysis. The crystallinity and stability of HP-MOFs remain after thermolabile linkers are selectively removed from multivariate metal-organic frameworks (MTV-MOFs) through a decarboxylation process. A domain-based linker spatial distribution was found to be critical for creating hierarchical pores inside MTV-MOFs. Furthermore, linker thermolysis promotes the formation of ultrasmall metal oxide nanoparticles immobilized in an open framework that exhibits high catalytic activity for Lewis acid-catalyzed reactions. Most importantly, this work provides fresh insights into the connection between linker apportionment and vacancy distribution, which may shed light on probing the disordered linker apportionment in multivariate systems, a long-standing challenge in the study of MTV-MOFs.
Feng, Liang,Yuan, Shuai,Zhang, Liang-Liang,Tan, Kui,Li, Jia-Luo,Kirchon, Angelo,Liu, Ling-Mei,Zhang, Peng,Han, Yu,Chabal, Yves J.,Zhou, Hong-Cai
supporting information
p. 2363 - 2372
(2018/02/19)

“Inverse” Frustrated Lewis Pairs: An Inverse FLP Approach to the Catalytic Metal Free Hydrogenation of Ketones
For the first time have boron-containing weak Lewis acids been demonstrated to be active components of Frustrated Lewis Pair (FLP) catalysts in the hydrogenation of ketones to alcohols. Combining the organosuperbase (pyrr)3P=NtBu with the Lewis acid 9-(4-CF3-C6H4)-BBN generated an “inverse” FLP catalyst capable of hydrogenating a range of aliphatic and aromatic ketones including N-, O- and S-functionalized substrates and bio-mass derived ethyl levulinate. Initial computational and experimental studies indicate the mechanism of catalytic hydrogenation with “inverse” FLPs to be different from conventional FLP catalysts that contain strong Lewis acids such as B(C6F5)3.
Mummadi, Suresh,Brar, Amandeep,Wang, Guoqiang,Kenefake, Dustin,Diaz, Rony,Unruh, Daniel K.,Li, Shuhua,Krempner, Clemens
supporting information
p. 16526 - 16531
(2018/10/20)

A method for synthesis of substituted cyclohexanol
The invention discloses a substituted cyclohexanol synthesis method. The substituted cyclohexanol synthesis method comprises that a phenolic compound as a raw material undergoes a one-step reaction in the presence of an amorphous alloy as a catalyst in a water phase to produce substituted cyclohexanol. The substituted cyclohexanol synthesis method is free of an organic solvent, has environmental friendliness, realizes high activity and high selectivity conversion of a phenolic compound into substituted cyclohexanol, has low energy consumption, is convenient for operation and prevents carbon deposition-caused catalyst deactivation.
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Paragraph 0045; 0046

(2017/08/25)

Selective C-F and C-H Activation of Fluoroarenes by Fe(PMe3)4 and Catalytic Performance of Iron Hydride in Hydrosilylation of Carbonyl Compounds
The reactions of perfluorinated toluene (CF3C6F5), pentafluoropyridine (C5NF5), and hexafluorobenzene (C6F6) with the iron(0) complex Fe(PMe3)4 were investigated. The Fe(I) complexes (4-CF3C6F4)Fe(PMe3)4 (1), (4-C5NF4)Fe(PMe3)4 (2), and (C6F5)Fe(PMe3)4 (3) were obtained by selective activation of the C-F bonds. However, under similar reaction conditions, the reaction of Fe(PMe3)4 with perfluoronaphthalene (C10F8) afforded a π-coordinated Fe(0) complex, (η4-1,2,3,4-C10F8)Fe(PMe3)3 (4), and the expected C-F bond activation reaction was not observed. The expected iron hydride (C6F5)FeH(PMe3)4 (6) could be obtained in a yield of 80% by the reaction of bromopentafluorobenzene with Fe(PMe3)4 and subsequent reduction with NaBH4. The molecular structures of complexes 2, 4, and 6 were determined by single-crystal X-ray diffraction. Complexes 1-4 and 6 could be used as catalysts for the hydrosilylation of carbonyl compounds. Among them, complex 6 is the best catalyst. The selective reduction of carbonyl groups of α,β-unsaturated aldehydes and ketones was also realized with 6 as catalyst.
Zheng, Tingting,Li, Junye,Zhang, Shumiao,Xue, Benjing,Sun, Hongjian,Li, Xiaoyan,Fuhr, Olaf,Fenske, Dieter
p. 3538 - 3545
(2016/11/06)

Selective hydrogenolysis of phenols and phenyl ethers to arenes through direct C-O cleavage over ruthenium-tungsten bifunctional catalysts
Direct hydrogenolysis of the aromatic Csp2-O bonds in both phenols and phenyl ethers to form arenes selectively is a core enabling technology that can expand greatly the scope of chemical manufacture from biomass. However, conventional hydrogenolysis of phenols typically led to aromatic ring saturation instead of the cleavage of the Csp2-O bonds. Herein, we report a recyclable Ru-WOx bifunctional catalyst that showed high catalytic activities for the hydrogenolysis of a wide range of phenols and phenyl ethers, including dimeric lignin model compounds and the primitive phenols separated from pyrolysis lignin, to form arenes selectively in water. Preliminary mechanistic studies supported that the reactions occurred via a direct cleavage of the Csp2-O bonds and the concerted effects of the hydrogenating Ru sites and the Lewis acidic W sites are the key to such an unusual reactivity.
Huang, Yao-Bing,Yan, Long,Chen, Meng-Yuan,Guo, Qing-Xiang,Fu, Yao
p. 3010 - 3017
(2015/05/27)

Catalytic hydrogenation of aromatic rings catalyzed by Pd/NiO
A simple and efficient heterogeneous palladium catalyst was prepared for aromatic ring hydrogenation. The catalyst was prepared by a reduction-deposition method and exhibited high activity and selectivity for the hydrogenation of a variety of substituted aromatic compounds to the corresponding cyclohexane and cyclohexanol derivatives with up to 99% yields. The catalyst was characterized by BET, TEM, XRD, XPS and ICP. Meanwhile the reusability of the catalyst was investigated, and it can be reused for several runs without significant deactivation.
Wang, Yanan,Cui, Xinjiang,Deng, Youquan,Shi, Feng
p. 2729 - 2732
(2014/01/06)

PVP-NiB amorphous catalyst for selective hydrogenation of phenol and its derivatives
PVP-NiB amorphous catalysts were prepared by the chemical reduction of nickel chloride with sodium borohydride, and characterized by infrared, X-ray diffraction, transmission election microscopy, and inductively coupled plasma. The relationship between the catalytic activity and nature of the active sites was discussed. PVP is a protective agent for preparing PVP-stabilized NiB catalysts, which improved the dispersion of the catalyst and stabilized its amorphous structure. The catalysis of phenol and its derivatives was evaluated in the aqueous phase. 99.9% conversion of phenol and 99.9% selectivity to cyclohexanol were obtained at 30 °C and 0.2 MPa H2 after 18 h over PVP-NiB. The generality of the PVP-NiB catalyst for this reaction was demonstrated by the selective hydrogenation of other phenol derivatives, which showed that the PVP-NiB catalyst was selective for the formation of cyclohexanol.
Zhang, Qinsheng,Li, Haifeng,Gao, Ping,Wang, Lailai
p. 1793 - 1799
(2015/09/28)

Highly efficient transfer hydrogenation of aldehydes and ketones using potassium formate over AlO(OH)-entrapped ruthenium catalysts
Ruthenium encapsulated in an aluminium oxyhydroxide-support was investigated for the transfer hydrogenation of aldehydes and ketones with potassium formate as a sustainable green hydrogen donor. The entrapped ruthenium were narrowly distributed with mean diameters of 1.5-1.8 nm. XPS studies show that the ruthenium was present as Ru0 and Ru3+. The catalysts showed high activity even at low metal loadings of 0.5-2 wt.%. The maximum TOF for benzaldehyde hydrogenation was over 1 wt.% Ru. The reduction of aromatic and aliphatic aldehydes was facile and occurred with 100% yield. In comparison, ketones were less readily reduced although moderate to excellent yields could be obtained after a longer reaction time. No leaching of ruthenium was observed in contrast to a catalyst prepared by wet impregnation. Washing of the used catalyst with water and ethanol effectively removed the deposited bicarbonate co-product and the recycled catalyst maintained its activity up to five runs.
Gao, Yanxiu,Jaenicke, Stephan,Chuah, Gaik-Khuan
p. 51 - 58
(2014/08/18)

Synthesis and properties of fluorous benzoquinones and their application in deprotection of silyl ethers
1,4-Benzoquinone derivatives bearing trifluoromethyl, perfluorobutyl and perfluorohexyl groups were prepared and employed in the deprotection of silyl ethers. The fluorous character of these compounds was examined by measuring the partition coefficient between the fluorous and organic solvents. The benzoquinone derivatives showed significant fluorous character, indicating that they can be recovered from the reaction mixtures using a fluorous/organic biphasic system. The oxidising ability of the fluorous benzoquinones was estimated by cyclic voltammetry, and these compounds were found to be strong oxidisers. The fluorous benzoquinones were utilised in the oxidative desilylation of silyl ethers to afford the deprotected alcohols in high yield. In addition, the reduced fluorous benzoquinones were recovered from the reaction mixtures in good yields using a fluorous/organic biphasic system. This journal is the Partner Organisations 2014.
Matsubara, Hiroshi,Maegawa, Takahiko,Kita, Yasuaki,Yokoji, Takato,Nomoto, Akihiro
p. 5442 - 5447
(2014/07/21)

Replacing phosphorus with sulfur for the efficient hydrogenation of esters
Catalyst tune-up: A readily available, air-stable amino-sulfide catalyst, [RuCl2(PPh3){HN(C2H4SEt) 2}], has been developed. This complex displays outstanding efficiency for the hydrogenation of a broad range of substrates with C-X bonds (esters, ketones, imines), as well as for the acceptorless dehydrogenative coupling of ethanol to ethyl acetate (see scheme). Copyright
Spasyuk, Denis,Smith, Samantha,Gusev, Dmitry G.
supporting information
p. 2538 - 2542
(2013/04/10)

Synthesis modulation as a tool to increase the catalytic activity of metal-organic frameworks: The unique case of UiO-66(Zr)
The catalytic activity of the zirconium terephthalate UiO-66(Zr) can be drastically increased by using a modulation approach. The combined use of trifluoroacetic acid and HCl during the synthesis results in a highly crystalline material, with partial substitution of terephthalates by trifluoroacetate. Thermal activation of the material leads not only to dehydroxylation of the hexanuclear Zr cluster but also to post-synthetic removal of the trifluoroacetate groups, resulting in a more open framework with a large number of open sites. Consequently, the material is a highly active catalyst for several Lewis acid catalyzed reactions.
Vermoortele, Frederik,Bueken, Bart,Le Bars, Gaelle,Van De Voorde, Ben,Vandichel, Matthias,Houthoofd, Kristof,Vimont, Alexandre,Daturi, Marco,Waroquier, Michel,Van Speybroeck, Veronique,Kirschhock, Christine,De Vos, Dirk E.
supporting information
p. 11465 - 11468
(2013/09/02)

A mild method for the deprotection of tetrahydropyranyl (THP) ethers catalyzed by iron(III) tosylate
A mild method for the deprotection of THP ethers catalyzed by iron(III) tosylate (2.0 mol %) in CH3OH has been developed. Iron(III) tosylate, Fe(OTs)3·6H2O, is a commercially available solid that is inexpensive, noncorrosive, and easy to handle. The room temperature reaction conditions make this method attractive for deprotection of a range of THP ethers.
Bockman, Matthew R.,Angeles, Veronica V.,Martino, Julia M.,Vagadia, Purav P.,Mohan, Ram S.
experimental part
p. 6939 - 6941
(2012/02/05)

Efficient stereo- and regioselective hydroxylation of alkanes catalysed by a bulky polyoxometalate
Direct functionalization of alkanes by oxidation of C-H bonds to form alcohols under mild conditions is a challenge for synthetic chemistry. Most alkanes contain a large number of C-H bonds that present difficulties for selectivity, and the oxidants employed often result in overoxidation. Here we describe a divanadium-substituted phosphotungstate that catalyses the stereo- and regioselective hydroxylation of alkanes with hydrogen peroxide as the sole oxidant. Both cyclic and acyclic alkanes were oxidized to form alcohols with greater than 96% selectivity. The bulky polyoxometalate framework of the catalyst results in an unusual selectivity that can lead to the oxidation of secondary rather than the weaker tertiary C-H bonds. The catalyst also avoids wasteful decomposition of the stoichiometric oxidant, which can result in the production of hydroxyl radicals and lead to non-selective oxidation and overoxidation of the desired products.
Kamata, Keigo,Yonehara, Kazuhiro,Nakagawa, Yoshinao,Uehara, Kazuhiro,Mizuno, Noritaka
scheme or table
p. 478 - 483
(2010/09/17)

Novel method of reducing ketones using sodium hydroxide in isopropanol
Ketones are readily reduced to secondary alcohols with sodium hydroxide in refluxing isopropanol.
Zuidema, Daniel R.,Wert, Katherine J.,Williams, Sarah L.,Chill, Samuel T.,Holte, Kimberly L.,Kokes, Nathanael K.,Mebane, Robert C.
experimental part
p. 1187 - 1191
(2010/04/28)

An iron-catalysed hydrosilylation of ketones
The combination of Fe(OAc)2 and multi-nitrogen-based ligands such as N,N,N′,N′-tetramethyethylenediamine, bis-tert-butyl- bipyridine, or bis(oxazolinyl)pyridine can efficiently catalyse hydrosilylation of ketones to give the corresponding alcohols in high yields including asymmetric catalysis. The Royal Society of Chemistry.
Nishiyama, Hisao,Furuta, Akihiro
p. 760 - 762
(2007/10/03)

Carbonyl reduction with CaH2 and R3SiCl catalyzed by ZnCl2
Ketones and aldehydes were effectively reduced to the corresponding alcohols (or their silyl ethers) by the reaction with CaH2 and R3SiCl in the presence of a catalytic amount of ZnCl2. In the absence of the carbonyl substrate, the reagent reduced R3SiCl to the corresponding hydrosilane under mild reaction conditions.
Tsuhako, Akiko,He, Jing-Qian,Mihara, Mariko,Saino, Naoko,Okamoto, Sentaro
p. 9120 - 9123
(2008/09/17)

Reduction of ketones to corresponding alcohols with magnesium metal in absolute alcohols
Various aliphatic and aromatic ketones are treated with 10 equiv of magnesium metal in absolute methanol or ethanol to afford corresponding alcohols in very high yields at room temperature within 12 h.
Kim, Ji Young,Kim, Hak Do,Seo, Min Jung,Kim, Hyoung Rae,No, Zaesung,Ha, Deok-Chan,Lee, Ge Hyeong
p. 9 - 12
(2007/10/03)

Deprotection of benzyl ethers using 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) under photoirradiation
The deprotection of benzyl ethers was effectively realized in the presence of 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) in MeCN under photoirradiation using a long wavelength UV light.
Rahim, Mohammad Abdur,Matsumura, Shuichi,Toshima, Kazunobu
p. 7307 - 7309
(2007/10/03)

Aromatic carbonyl compound reduction and pinacol coupling processes mediated by titanocene(III)/Zn in water
A novel procedure for the reduction and pinacol coupling of aromatic aldehydes and ketones mediated by titanocene(III)/Zn in water is described. The titanocene-catalyzed version in sea water proved to be especially convenient for the reduction of aryl ketones. Mechanistically, the reaction presumably proceeds via free-radical chemistry. Georg Thieme Verlag Stuttgart.
Oller-Lopez, Juan L.,Campana, Araceli G.,Cuerva, Juan M.,Oltra, J. Enrique
p. 2619 - 2622
(2007/10/03)

Regioselective samarium diiodide induced couplings of carbonyl compounds with 1,3-diphenylallene and alkoxyallenes: A new route to 4-hydroxy-1-enol ethers
Since its introduction into synthetic organic chemistry, samarium diiodide has found broad application in a variety of synthetically important transformations. Herein, we describe the first successful intermolecular additions of samarium ketyls to typical allenes such as 1,3-diphenylallene (7), methoxyallene (12) and benzyloxyallene (25). Reaction of different samarium ketyls with 1,3-diphenylallene (7) occurred exclusively at the central carbon atom of the allene to afford products 9 in moderate to good yields. In contrast, reductive coupling of cyclic ketones to methoxyallene (12) regioselectively provided 4-hydroxy-1-enol ethers 13, which derive from addition to the terminal allene carbon atom of 12, in moderate to good yields. Whereas the E/Z selectivity with respect to the enol ether double bond is low, excellent diastereoselectivity has been observed in certain cases with regard to the ring configuration (e.g. compound 13 b). Studies with deuterated tetrahydrofuran and alcohol were performed to gain information about the reaction mechanism of this coupling process, which involves alkenyl radicals. The couplings of samarium ketyls derived from acyclic ketones and aldehydes gave lower yields, and in several cases cyclopentanols 20 are formed as byproducts. Branched acyclic ketones and conformationally more flexible cyclic ketones such as cycloheptanone led to a relatively high amount of cyclopentanol derivatives 20, whose formation involves an intramolecular hydrogen atom transfer through a geometrically favoured six-membered transition state followed by a cyclization step. The samarium diiodide mediated addition of 8b to benzyloxyallene (25) afforded the expected enol ethers 26, albeit in only low yield. Additionally, spirocyclic compounds 27 and 28 were obtained, which are formed by a cascade reaction involving an addition/cyclization sequence. In the novel coupling process described here methoxyallene (12) serves as an equivalent of acrolein. The 1,4-dioxygenated products obtained contain a masked aldehyde functionality and are therefore valuable building blocks in organic synthesis.
Hoelemann, Alexandra,Reissig, Hans-Ulrich
p. 5493 - 5506
(2007/10/03)

Rapid racemization of chiral non-racemic sec-alcohols catalyzed by (η5-C5(CH3)5)Ru complexes bearing tertiary phosphine-primary amine chelate ligands
A ternary catalyst system of Cp* RuCl(cod)-2-diphenylphosphinoethylamine-KOt-Bu (Cp=η 5-C5(CH3)5, cod=1,5-cyclooctadiene) causes rapid racemization of chiral non-racemic sec-alcohols, which results from the reversible hydrogen transfer between sec-alcohols and ketones. Both tertiary phosphine and primary amine functionalities in the ligand are responsible for the high rate.
Ito, Masato,Osaku, Akihide,Kitahara, Sachiko,Hirakawa, Makoto,Ikariya, Takao
p. 7521 - 7523
(2007/10/03)

A free radical method for reduction of cyclohexanones - Preferential formation of equatorial alcohols
Cyclohexanones react with 2-hydroselenobenzoic acid to afford spiro-[4H-3,1-benzoxaselenin-2,1′-cyclohexan]-4-ones. Stannane reduction and basic hydrolysis gives epimeric cyclohexanols, with the equatorial isomer predominating.
Clive, Derrick L. J.,Cheng, Hua
p. 1951 - 1961
(2007/10/03)

Deprotection of benzyl and p-methoxybenzyl ethers by chlorosulfonyl isocyanate-sodium hydroxide
CSI-NaOH procedure provided a new and mild methodology for the deprotection of benzyl and p-methoxybenzyl ethers without affecting the other functional groups under similar reaction conditions.
Kim, Ji Duck,Han, Gyoonhee,Zee, Ok Pyo,Jung, Young Hoon
p. 733 - 735
(2007/10/03)

Titanocene-catalysed, selective reduction of ketones in aqueous media. A safe, mild, inexpensive procedure for the synthesis of secondary alcohols via radical chemistry
We report here a novel procedure for the reduction of ketones to secondary alcohols using catalytic quantities of commercially available Cp2TiCl2, inexpensive Zn dust and water as proton source. Mechanistically the reaction presumably proceeds via titanoxy radicals. In practice this reduction process has significant advantages: it shows an interesting selectivity pattern, takes place under mild conditions using safe, cheap reagents and does not require anhydrous solvents. The proton-donor activity of water under these conditions avoids the use of the frequently poisonous hydrogen-atom donors generally required to reduce free radicals. This procedure is also highly convenient for synthesising deuterium-labelled alcohols employing relatively inexpensive D2O as deuterium source.
Barrero, Alejandro F.,Rosales, Antonio,Cuerva, Juan M.,Gans?uer, Andreas,Oltra, J. Enrique
p. 1079 - 1082
(2007/10/03)

Water-resistant solid Lewis acid catalysts: Meerwein-Ponndorf-Verley and Oppenauer reactions catalyzed by tin-beta zeolite
The catalytic activity of Sn-beta zeolite in the Meerwein-Pondorf-Verley reduction of carbonyl compounds with secondary alcohols as reductants and Oppenauer oxidation of alcohols were performed with quantitative yields to the corresponding product. The catalyst had an excellent activity and selectivity even after four catalytic recycles, and good stereoselectivities to the thermodynamic less favorable cis-alcohol isomer when alkyl-cyclohexanones were used as substrates. A prochiral ketone was reduced within an enantiomeric excess close to 50% when using a chiral alcohol as the reducing reactant. IR studies using cyclohexanone as probe molecule over beta zeolites showed that the more specific Lewis acid sites in the framework of Sn-beta were responsible for its better catalytic activity with respect to Ti- or Al-beta. The order of hydrophobicity of the samples was Ti-beta > Sn-beta > Al-beta. Ti-beta and Sn-beta retained a higher percentage of catalytic activity when water was present in the reaction media. Even with ～ 4 wt % of H2O (0.2 g) in the media, Sn-beta yielded a higher turnover number than Ti- or Al-beta when working in the absence of water.
Corma, Avelino,Domine, Marcelo E.,Valencia, Susana
p. 294 - 304
(2007/10/03)

Cleavage of a p-cyanobenzyl group from protected alcohols, amines, and thiols using triethylgermyl sodium
Alcohols, amines, and thiols protected with a p-cyanobenzyl group can be easily and quantitatively deprotected using triethylgermyl sodium under mild conditions.
Yokohama, Yasuo,Takizawa, Shuichi,Nanjo, Masato,Mochida, Kunio
p. 1032 - 1033
(2007/10/03)

Process for preparing reductants of unsaturated organic compounds by the use of trichlorosilane and reducing agents
A method of preparing a reduced product by efficiently reducing an unsaturated organic compound by using, as a reducing agent, a trichlorosilane which is industrially cheaply available and is easy to handle, and a reducing agent therefor. A reduced product of an unsaturated organic compound is obtained by mixing the unsaturated organic compound and a trichlorosilane together to reduce the unsaturated organic compound in the presence of a compound that forms a silicon complex having five coordinations upon acting on the trichlorosilane such as an N-formylated product of a secondary amine having not less than 3 carbon atoms. The invention further provides a reducing agent comprising a particular silicon complex.
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(2008/06/13)

Compounds having protected hydroxy groups
The present invention relates to compounds with protected hydroxy groups of formula (I) These compounds are precursors for organoleptic agents, such as fragrances, and masking agents and for antimicrobial agents. When activated, the compounds of formula (I) are cleaved and form one or more organoleptic and/or antimicrobial compounds.
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(2008/06/13)

Process for reacting an organic compound in the presence of a supported ruthenium catalyst
A process for the reaction of an organic compound in the presence of a catalyst comprising, as active metal, ruthenium alone or together with at least one Group Ib, VIIb, or VIIIb metal in an amount of from 0.01 to 30 wt %, based on the total weight of the catalyst, applied to a support, wherein from 10 to 50% of the pore volume of the support comprises macropores having a pore diameter in the range of from 50 nm to 10,000 nm and from 50 to 90% of the pore volume of the support comprises mesopores having a pore diameter in the range of from 2 to 50 nm, the sum of said pore volumes being 100%, and said catalyst as such.
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Page column 17

(2008/06/13)

Method for reducing a carbonyl-containing compound
A subject of the present invention is a process for the reduction of a carbonyl compound. More precisely, the invention relates to a process for reduction of an aldehyde and/or of a ketone. The reduction process of the invention, which consists of reacting a carbonyl compound with an alcohol in the presence of a zeolite catalyst, is characterized by the fact that it comprises: mixing, in any manner whatever, the carbonyl compound and the alcohol, passing said mixture over a catalyst bed containing at least one zeolite, subjecting the reaction mixture leaving the catalyst bed to recirculation over the catalyst bed, for a number of times that is sufficient to obtain the desired degree of conversion of the substrate.
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Example 5

(2008/06/13)

Meerwein-Ponndorf-Verley reduction of cycloalkanones over magnesium-aluminium oxide
MgO-Al2O3 obtained from layered double hydroxide has been studied as a catalyst in the Meerwein-Ponndorf-Verley (MPV) reduction of cycloalkanones and substituted cyclohexanones in the liquid phase. Conversions for cycloalkanones always exceeded 95% and the selectivity was 100% within thefirst 10h of reaction. In the MPV reduction of 4-tert-butylcyclohexanone to 4-tert-butylcyclohexanol a high stereoselectivity (cis:trans ratio > 12) was obtained. This stereoselectivity is explained by the transition-state selectivity imposed by the adsorption complex. For the reduction of cyclohexanone, a recycling test showed that the catalyst can be reused up to four times without losing more than 10% catalytic activity.
Aramendía, María A.,Borau, Victoriano,Jiménez, César,Marinas, José M.,Ruiz, José R.,Urbano, Francisco J.
p. 1122 - 1125
(2007/10/03)

Cu/SiO2-catalyzed hydrogenation of cyclohexanones under very mild conditions
Unsubstituted and alkyl-substituted cyclohexanones, including 3-oxo-steroids, can be easily hydrogenated to the corresponding alcohols at 1 atm of H2 and 60-90°C over a 8% Cu/SiO2 non-toxic, reusable catalyst with excellent selectivity.
Ravasio, Nicoletta,Psaro, Rinaldo,Zaccheria, Federica
p. 3943 - 3945
(2007/10/03)

Photochemically removable silyl protecting groups
Several o-phenol-containing alkoxyvinylsilanes were prepared and their photochemistry was investigated. These materials were prepared via hydrosilylation of the corresponding o-acetoxy arylacetylenes. Two major classes of photochemical processes were identified in these reactants: trans→cis isomerization, leading to an intramolecular nucleophilic substitution process at silicon, and 1,5-silyl shift, leading to an unsymmetrical dialkoxysilane. The major outcome of this work is a novel class of photochemically removable protecting groups. Two alkyl substitutions on silicon, the dimethyl and diisopropyl, were examined. The latter is more stable and is preferred for protecting groups that must tolerate multiple steps or reagents. Protection of alcohols is generally performed starting with the arylethynyl acetate, which can be subjected to hydrosilylation, alcohol substitution, and acetate deprotection without isolation of intermediates. Two groups were studied in detail, the phenol and 2-naphthol vinyl silane derivatives. A variety of primary and secondary alcohols were protected with these reagents. These groups can be deprotected cleanly and in high yield by irradiation from 250 to 350 nm.
Pirrung,Fallon,Zhu,Yong Rok Lee
p. 3638 - 3643
(2007/10/03)

PERFUME COMPOSITION
A perfume composition contains specified ketones, salicylates and alcohols/acetates/propionates. Use of such a perfume composition inhibits development of human body malodour. The combination of specified materials makes it possible to avoid inclusion of individual components with powerful, unacceptable odours. The perfume composition may be used in various products notably in a fabric conditioning product used during the rinsing or tumble drying of fabrics after washing to soften the fabrics.
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(2008/06/13)

Synthesis of solid-phase bound sulfonate esters
p-Pivaloyloxybenzenesulfonyl and methylsulfonyl residues were used as linkers to attach secondary alcohols to Wang resin and to Merrifield resin, respectively. p-Pivaloyloxybenzenesulfonates of alcohols were deprotected at the phenolic group and coupled with Wang resin by Mitsunobu reaction whereas mesylates were lithiated at the methyl group and subsequently connected with chloromethyl residues of Merrifield resin.
Furman,Lysek,Matyjasek,Wojtkielewicz,Chmielewski
p. 2795 - 2802
(2007/10/03)

An examination of hyperconjugative and electrostatic effects in the hydride reductions of 2-substituted-4-tert-butylcyclohexanones
To better understand electronic effects on the diastereoselectivity of nucleophilic additions to the carbonyl group, a series of 2-X-4-tert-butylcyclohexanones (X = H, CH3, OCH3, F, Cl, Br) were reacted with LiAlH4. Reduction of ketones with equatorial substituents yields increasing amounts of axial alcohol in the series for X {H 3 3}. These data cannot be explained by steric or chelation ·effects or by the theories of Felkin-Anh or Cieplak. Instead, an electrostatic argument is introduced: due to repulsion between the nucleophile and the X group, axial approach becomes energetically less favorable with an increase in the component of the dipole moment anti to the hydride approach trajectory. The ab initio calculated diastereoselectivities were close to the experimental values but did not reproduce the relative selectivity ordering among substituents. For reduction of ketones with axial substituents, increasing amounts of axial alcohol are seen in the series for X {Cl 3 3 H F}. After some minor adjustments are made, this ordering is consistent with both the electrostatic model and Felkin-Anh theory. Cieplak theory cannot account for these data regardless of adjustments. Ab initio calculated diastereoselectivities were reasonably accurate for the nonpolar substituents but were poor for the polar substituents.
Rosenberg,Abei,Drake,Fox,Ignatz,Kwiat,Schaal,Virkler
p. 1694 - 1700
(2007/10/03)

Acceleration of ruthenium(II)- and rhodium(I)-catalyzed hydrogen-transfer reaction by rare earth metal triflates
The addition of Yb(OTf)3 as an additive considerably accelerates the RuCl2(PPh3)3- and RhCl(PPh3)3-catalyzed hydrogen-transfer reduction of both aromatic and aliphatic ketones in which Ru:Yb ratios of 1:2-1:4 are critically important for achieving acceleration.
Matsunaga, Hirofumi,Yoshioka, Naoko,Kunieda, Takehisa
p. 8857 - 8859
(2007/10/03)