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Continuous synthesis of menthol from citronellal and citral over Ni-beta-zeolite-sepiolite composite catalyst
One-pot continuous synthesis of menthols both from citronellal and citral was investigated over 5 wt% Ni supported on H-Beta-38-sepiolite composite catalyst at 60–70 °C under 10–29 bar hydrogen pressure. A relatively high menthols yield of 53% and 49% and stereoselectivity to menthol of 71–76% and 72–74% were obtained from citronellal and citral respectively at the contact time 4.2 min, 70 °C and 20 bar. Citral conversion noticeably decreased with time-on-stream under 10 and 15 bar of hydrogen pressure accompanied by accumulation of citronellal, the primary hydrogenation product of citral, practically not affecting selectivity to menthol. A substantial amount of defuctionalization products observed during citral conversion, especially at the beginning of the reaction (ca. 1 h), indicated that all intermediates could contribute to formation of menthanes. Ni/H-Beta-38-sepiolite composite material prepared by extrusion was characterized by TEM, SEM, XPS, XRD, ICP-OES, N2 physisorption and FTIR techniques to perceive the interrelation between the physico-chemical and catalytic properties.
Er?nen, Kari,M?ki-Arvela, P?ivi,Martinez-Klimov, Mark,Muller, Joseph,Murzin, Dmitry Yu.,Peurla, Markus,Simakova, Irina,Vajglova, Zuzana
(2022/04/03)

Nickel-catalyzed reductive 1,3-diene formation from the cross-coupling of vinyl bromides
Facile construction of 1,3-dienes building upon cross-electrophile coupling of two open-chain vinyl halides is disclosed in this work, showing moderate chemoselectivities between the terminal bromoalkenes and internal vinyl bromides. The present method is mild and tolerates a range of functional groups and can be applied to the total synthesis of a tobacco fragrance solanone.
Sha, Yunfei,Liu, Jiandong,Wang, Liang,Liang, Demin,Wu, Da,Gong, Hegui
supporting information
p. 4887 - 4890
(2021/06/16)

Nanocomposite Hydrogel of Pd@ZIF-8 and Laponite: Size-Selective Hydrogenation Catalyst under Mild Conditions
The composite hydrogel of a nanoscale metal–organic framework (NMOF) and nanoclay has emerged as a new soft-material with advanced properties and applications. Herein, we report a facile synthesis of a hydrogel nanocomposite by charge-assisted self-assembly of Pd@ZIF-8 nanoparticles with Laponite nanoclay which coat the surface of Pd@ZIF-8 nanoparticles. Such surface coating significantly enhanced the thermal stability of the ZIF-8 compared to the pristine framework. Further, the Pd@ZIF-8+LP hydrogel nanocomposite shows better size-selective catalytic hydrogenation of olefins than Pd@ZIF-8 nanoparticles based on selective diffusion of the substrate.
Sutar, Papri,Bakuru, Vasudeva Rao,Yadav, Pooja,Laha, Subhajit,Kalidindi, Suresh Babu,Maji, Tapas Kumar
supporting information
p. 3268 - 3272
(2021/01/21)

RhNPs supported onN-functionalized mesoporous silica: effect on catalyst stabilization and catalytic activity
Amine and nicotinamide groups grafted on ordered mesoporous silica (OMS) were investigated as stabilizers for RhNPs used as catalysts in the hydrogenation of several substrates, including carbonyl and aryl groups. Supported RhNPs on functionalized OMS were prepared by controlled decomposition of an organometallic precursor of rhodium under dihydrogen pressure. The resulting materials were characterized thoroughly by spectroscopic and physical techniques (FTIR, TGA, BET, SEM, TEM, EDX, XPS) to confirm the formation of spherical rhodium nanoparticles with a narrow size distribution supported on the silica surface. The use of nicotinamide functionalized OMS as a support afforded small RhNPs (2.3 ± 0.3 nm), and their size and shape were maintained after the catalyzed acetophenone hydrogenation. In contrast, amine-functionalized OMS formed RhNP aggregates after the catalytic reaction. The supported RhNPs could selectively reduce alkenyl, carbonyl, aryl and heteroaryl groups and were active in the reductive amination of phenol and morpholine, using a low concentration of the precious metal (0.07-0.18 mol%).
Pulido-Díaz, Israel T.,Serrano-Maldonado, Alejandro,López-Suárez, Carlos César,Méndez-Ocampo, Pedro A.,Portales-Martínez, Benjamín,Gutiérrez-Alejandre, Aída,Salas-Martin, Karla P.,Guerrero-Ríos, Itzel
p. 3289 - 3298
(2021/03/16)

Chemoselective and Tandem Reduction of Arenes Using a Metal–Organic Framework-Supported Single-Site Cobalt Catalyst
The development of heterogeneous, chemoselective, and tandem catalytic systems using abundant metals is vital for the sustainable synthesis of fine and commodity chemicals. We report a robust and recyclable single-site cobalt-hydride catalyst based on a porous aluminum metal–organic framework (DUT-5 MOF) for chemoselective hydrogenation of arenes. The DUT-5 node-supported cobalt(II) hydride (DUT-5-CoH) is a versatile solid catalyst for chemoselective hydrogenation of a range of nonpolar and polar arenes, including heteroarenes such as pyridines, quinolines, isoquinolines, indoles, and furans to afford cycloalkanes and saturated heterocycles in excellent yields. DUT-5-CoH exhibited excellent functional group tolerance and could be reusable at least five times without decreased activity. The same MOF-Co catalyst was also efficient for tandem hydrogenation–hydrodeoxygenation of aryl carbonyl compounds, including biomass-derived platform molecules such as furfural and hydroxymethylfurfural to cycloalkanes. In the case of hydrogenation of cumene, our spectroscopic, kinetic, and density functional theory (DFT) studies suggest the insertion of a trisubstituted alkene intermediate into the Co–H bond occurring in the turnover limiting step. Our work highlights the potential of MOF-supported single-site base–metal catalysts for sustainable and environment-friendly industrial production of chemicals and biofuels.
Akhtar, Naved,Begum, Wahida,Chauhan, Manav,Manna, Kuntal,Newar, Rajashree,Rawat, Manhar Singh
supporting information

(2022/01/19)

Acidic metal-organic framework empowered precise hydrodeoxygenation of bio-based furan compounds and cyclic ethers for sustainable fuels
Target synthesis of hydrocarbons from abundant biomass is highly desired for sustainable aviation fuels (SAFs) to meet the need for both net zero carbon emission and air pollution control. However, precise hydrodeoxygenation (PHDO) of bio-based furan compounds and cyclic ethers to isomerically pure alkanes remains a challenge in heterogenous catalysis, which usually requires delicate control of the distribution of acid and metal catalytic sites in nanoconfined space. Here we show that a nanoporous acidic metal-organic framework (MOF), namely MIL-101-SO3H, enables one-pot PHDO reactions from furan-derivative oxygenates to solely single-component alkanes by just mechanical mixing with commercial Pd/C towards highly efficient and highly selective hydrocarbon production. The superior performance of such tandem catalysts can be attributed to the preferential adsorption of oxygenate precursors and expulsion of deoxygenated intermediates benefiting from Lewis acid sites embedded in the MOF. The strong Br?nsted acidity of MIL-101-SO3H is contributed by both the -SO3H groups and the adsorbed H2O, which makes it a water-tolerant solid acid for durable PHDO processes. The simplicity of mechanical mixing of different heterogenous catalysts allows the modulation of the tandem catalysis system for optimization of the ultimate catalytic performance. This journal is
Gao, Xiang-Yu,He, Hai-Long,Li, Zhi,Liu, Dong-Huang,Wang, Jun-Jie,Xiao, Yao,Yi, Xianfeng,Zeng, Tengwu,Zhang, Yue-Biao,Zheng, Anmin,Zhou, Si-Yu
supporting information
p. 9974 - 9981
(2021/12/27)

STRONGLY LEWIS ACIDIC METAL-ORGANIC FRAMEWORKS FOR CONTINUOUS FLOW CATALYSIS
Lewis acidic metal-organic framework (MOF) materials comprising triflate-coordinated metal nodes are described. The materials can be used as heterogenous catalysts in a wide range of organic group transformations, including Diels-Alder reactions, epoxide-ring opening reactions, Friedel-Crafts acylation reactions and alkene hydroalkoxylation reactions. The MOFs can also be prepared with metallated organic bridging ligands to provide heterogenous catalysts for tandem reactions and/or prepared as composites with support particles for use in columns of continuous flow reactor systems. Methods of preparing and using the MOF materials and their composites are also described.
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(2021/02/26)

Multistep Engineering of Synergistic Catalysts in a Metal-Organic Framework for Tandem C-O Bond Cleavage
Cleavage of strong C-O bonds without breaking C-C/C-H bonds is a key step for catalytic conversion of renewable biomass to hydrocarbon feedstocks. Herein we report multistep sequential engineering of orthogonal Lewis acid and palladium nanoparticle (NP) catalysts in a metal-organic framework (MOF) built from (Al-OH)n secondary building units and a mixture of 2,2′-bipyridine-5,5′-dicarboxylate (dcbpy) and 1,4-benzenediacrylate (pdac) ligands (1) for tandem C-O bond cleavage. Ozonolysis of 1 selectively removed pdac ligands to generate Al2(OH)(OH2) sites, which were subsequently triflated with trimethylsilyl triflate to afford strongly Lewis acidic sites for dehydroalkoxylation. Coordination of Pd(MeCN)2Cl2 to dcbpy ligands followed by in situ reduction produced orthogonal Pd NP sites in 1-OTf-PdNP as the hydrogenation catalyst. The selective and precise transformation of 1 into 1-OTf-PdNP was characterized step by step using powder X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, inductively coupled plasma mass spectrometry, infrared spectroscopy, and X-ray absorption spectroscopy. The hierarchical incorporation of orthogonal Lewis acid and Pd NP active sites endowed 1-OTf-PdNP with outstanding catalytic performance in apparent hydrogenolysis of etheric, alcoholic, and esteric C-O bonds to generate saturated alkanes via a tandem dehydroalkoxylation-hydrogenation process under relatively mild conditions. The reactivity of C-O bonds followed the trend of tertiary carbon > secondary carbon > primary carbon. Control experiments demonstrated the heterogeneous nature and recyclability of 1-OTf-PdNP and its superior catalytic activity over the homogeneous counterparts. Sequential engineering of multiple catalytic sites in MOFs thus presents a unique opportunity to address outstanding challenges in sustainable catalysis.
Brzezinski, Carter,Chen, Justin S.,Feng, Xuanyu,Lin, Wenbin,Song, Yang,Xu, Ziwan
supporting information
p. 4872 - 4882
(2020/04/01)

Scalable Total Synthesis of (-)-Vinigrol
Vinigrol is a structurally and stereochemically complex natural product that displays various potent pharmacological activities, including the capability to modulate TNF-α. A new and efficient synthetic route toward this natural product has been developed to complete the asymmetric synthesis of (-)-vinigrol and provide over 600 mg of material, manifesting the power of macrocyclic stereocontrol and transannular Diels-Alder reaction.
Yu, Xuerong,Xiao, Lianghong,Wang, Zechun,Luo, Tuoping
supporting information
p. 3440 - 3443
(2019/03/07)

Identification of an Asexual Reproduction Inducer of Phytopathogenic and Toxigenic Fusarium
Asexual and sexual reproduction are the most important biological events in the life cycle of phytopathogenic and toxigenic Fusarium and are responsible for disease epidemics. However, the signaling molecules which induce the asexual reproduction of Fusarium are unknown. Herein we describe the structure elucidation, including the absolute configuration, of Fusarium asexual reproduction inducer (FARI), a new sesquiterpene derivative, by spectroscopic analysis, total synthesis, and conidium-inducing assays of synthetic isomers. We have also uncovered the universality of FARI among Fusarium species. Moreover, a mechanism-of-action study suggested that the Gpmk1 and LaeA signaling pathways are required for conidium formation induced by FARI; conversely, the Mgv1 of mitogen-activated protein kinase is not involved in conidium formation. FARI exhibited conidium-inducing activity at an extremely low dose and high stereoselectivity, which may suggest the presence of a stereospecific target.
Qi, Jianhua,Cheng, Lihong,Sun, Yujuan,Hirata, Yushi,Ushida, Naoki,Ma, Zhonghua,Osada, Hiroyuki,Nishikawa, Toshio,Xiang, Lan
supporting information
p. 8100 - 8104
(2018/06/04)

Efficient hydro-deoxygenation of lignin derived phenolic compounds over bifunctional catalysts with optimized acid/metal interactions
Efficient hydro-deoxygenation (HDO) of lignin derived phenolic compounds was a challenging task due to the incompatibility of the phenolic feedstock and the current hydro-processing catalysts. In this paper, hydro-deoxygenation of lignin derived phenolic compounds over a series of bifunctional catalysts with different metal/acid interactions was firstly carried out. It was found that the distance between the acidic site and noble metal played an important role in the catalytic performance of phenolic hydro-deoxygenation. A highly stable bifunctional catalyst for hydro-deoxygenation of lignin derived phenolic compounds was obtained through simple selective deposition of Pt on alumina in a commonly used Al2O3-ZSM-5 nanocomposite. The bifunctional catalyst retained its complete deoxygenation capacity for more than 500 h. The catalyst can also be used for the HDO of various phenolic model compounds and real bio-oil derived from lignin. A correction of the generally accepted the closer the better criterion in metal/acid bifunctional catalysts when used in bio-oxygenate HDO was also discussed.
Ju, Chao,Li, Mingrui,Fang, Yunming,Tan, Tianwei
supporting information
p. 4492 - 4499
(2018/10/24)

Structural, electronic and catalytic properties of palladium nanoparticles supported on poly(ionic liquid)
The structural, electronic and support effect on palladium nanoparticles (Pd NPs) prepared by sputtering deposition and chemical reduction of a Pd(II) precursor in/on a poly(ionic liquid) (PIL) was investigated in the selective hydrogenation of α,β-unsaturated carbonyl compounds and dienes. Sputtering deposition generates naked NPs with a narrow size distribution (3.2–3.8 nm) that are predominantly composed of Pd(0) (85–100%). Conversely, chemical reduction produces PIL-covered NPs with almost twice the average size (6.6 nm) and only 15% Pd(0). Regard the catalytic performance, support composition (by ionic liquid (IL) addition or not) and NP location are decisive. The best activity and selectivity was obtained with imprinted Pd NPs on a PIL/IL mixture (D-MPIL.NTf2/IL-Pd catalyst). A kinetic investigation was conducted using 2-cyclohexen-1-one (CHN) and D-MPIL.NTf2/IL-Pd catalyst revealing that this reaction follows the Langmuir-Hinshelwood mechanism. Enthalpies obtaining from a Van't Hoff plot show that the adsorption of the CHN substrate on the surface of the PIL-Pd catalyst is an exothermic process (-9 kJ mol?1), whereas H2 adsorption occurs by an endothermic process (12 kJ mol?1). This distinct behavior is consistent with the rate determining step proposed, in which the independent adsorption of reagents is followed by the hydrogenation of a π-allyl intermediate on the catalyst surface.
Simon, Nathália M.,Abarca, Gabriel,Scholten, Jackson D.,Domingos, Josiel B.,Mecerreyes, David,Dupont, Jairton
p. 79 - 86
(2018/06/11)

STABILIZATION OF ACTIVE METAL CATALYSTS AT METAL-ORGANIC FRAMEWORK NODES FOR HIGHLY EFFICIENT ORGANIC TRANSFORMATIONS
Metal-organic framework (MOFs) compositions based on post?synthetic metalation of secondary building unit (SBU) terminal or bridging OH or OH2 groups with metal precursors or other post-synthetic manipulations are described. The MOFs provide a versatile family of recyclable and reusable single-site solid catalysts for catalyzing a variety of asymmetric organic transformations, including the regioselective boryiation and siiylation of benzyiic C—H bonds, the hydrogenation of aikenes, imines, carbonyls, nitroarenes, and heterocycles, hydroboration, hydrophosphination, and cyclization reactions. The solid catalysts can also be integrated into a flow reactor or a supercritical fluid reactor.
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(2019/01/07)

Single-Site Cobalt Catalysts at New Zr8(μ2-O)8(μ2-OH)4 Metal-Organic Framework Nodes for Highly Active Hydrogenation of Alkenes, Imines, Carbonyls, and Heterocycles
We report here the synthesis of robust and porous metal-organic frameworks (MOFs), M-MTBC (M = Zr or Hf), constructed from the tetrahedral linker methane-tetrakis(p-biphenylcarboxylate) (MTBC) and two types of secondary building units (SBUs): cubic M8(μ2-O)8(μ2-OH)4 and octahedral M6(μ3-O)4(μ3-OH)4. While the M6-SBU is isostructural with the 12-connected octahedral SBUs of UiO-type MOFs, the M8-SBU is composed of eight MIV ions in a cubic fashion linked by eight μ2-oxo and four μ2-OH groups. The metalation of Zr-MTBC SBUs with CoCl2, followed by treatment with NaBEt3H, afforded highly active and reusable solid Zr-MTBC-CoH catalysts for the hydrogenation of alkenes, imines, carbonyls, and heterocycles. Zr-MTBC-CoH was impressively tolerant of a range of functional groups and displayed high activity in the hydrogenation of tri- and tetra-substituted alkenes with TON > 8000 for the hydrogenation of 2,3-dimethyl-2-butene. Our structural and spectroscopic studies show that site isolation of and open environments around the cobalt-hydride catalytic species at Zr8-SBUs are responsible for high catalytic activity in the hydrogenation of a wide range of challenging substrates. MOFs thus provide a novel platform for discovering and studying new single-site base-metal solid catalysts with enormous potential for sustainable chemical synthesis.
Ji, Pengfei,Manna, Kuntal,Lin, Zekai,Urban, Ania,Greene, Francis X.,Lan, Guangxu,Lin, Wenbin
supporting information
p. 12234 - 12242
(2016/09/28)

Colloidal and nanosized catalysts in organic synthesis: XV. Gas-phase hydrogenation of alkenes catalyzed by supported nickel nanoparticles
Gas-phase hydrogenation of alkenes and their derivatives, catalyzed by nickel nanoparticles supported on zeolite or silica gel support occurs at 150–250°С and an atmospheric hydrogen pressure and results in a high conversion. The selectivity of the hydrogenation depends on the amount of hydrogen: at a low diene (triene)–hydrogen ratio, selective hydrogenation of one multiple bond in the substrate is possible.
Popov, Yu. V.,Mokhov,Nebykov,Latyshova,Panov,Dontsova,Shirkhanyan,Shcherbakova
p. 2589 - 2593
(2017/03/22)

Mechanisms into dehydroaromatization of bio-derived limonene to: P -cymene over Pd/HZSM-5 in the presence and absence of H2
The mechanisms of dehydroaromatization of limonene to p-cymene are intrinsically investigated over Pd/HZSM-5 under different N2/H2 atmospheres using the mathematical tool of Matlab. It is found that the dehydroaromatization reaction network starts with the isomerization step, and is followed by the sequential dehydrogenation in the presence of N2 or H2 at the selected system. The addition of hydrogen in the atmosphere would not change this reaction pathway, but leads to lower selectivity of p-cymene due to the accelerated hydrogenation rates on the double bonds. Besides, the additional hydrogen speeds up the overall reaction by facilitating the isomerization step on limonene while impeding its reverse reaction, as isomerization of limonene is proved to be the determining step of the whole dehydroaromatization reaction. Furthermore, the presence of hydrogen dramatically decreases the apparent and true activity energy of the target dehydroaromatization reaction and reduces the impact of temperatures to such processes compared to that with a N2 gas carrier.
Cui, Huimei,Zhang, Jingjing,Luo, Zhicheng,Zhao, Chen
p. 66695 - 66704
(2016/08/02)

Method of producing hydrogen of the reaction product and substrate
PROBLEM TO BE SOLVED: To provide a new production method requiring no reactor having high stirring power for high-temperature and high-pressure conditions in a gas-liquid catalytic reaction of a liquid phase of a substrate with hydrogen in the presence of a solid catalyst. SOLUTION: Micro or nano bubbles are introduced into a liquid phase consisting of a solvent and a substrate so that a reaction product is produced by gas-liquid contact of the substrate with hydrogen in the presence of the solid catalyst. The substrate is one of organic compounds having an unsaturated carbon bond and secondary and tertiary alcohols. COPYRIGHT: (C)2013,JPOandINPIT
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(2017/03/24)

Metal-Organic Frameworks Stabilize Solution-Inaccessible Cobalt Catalysts for Highly Efficient Broad-Scope Organic Transformations
New and active earth-abundant metal catalysts are critically needed to replace precious metal-based catalysts for sustainable production of commodity and fine chemicals. We report here the design of highly robust, active, and reusable cobalt-bipyridine- and cobalt-phenanthroline-based metal-organic framework (MOF) catalysts for alkene hydrogenation and hydroboration, aldehyde/ketone hydroboration, and arene C-H borylation. In alkene hydrogenation, the MOF catalysts tolerated a variety of functional groups and displayed unprecedentedly high turnover numbers of ～2.5 × 106 and turnover frequencies of ～1.1 × 105 h-1. Structural, computational, and spectroscopic studies show that site isolation of the highly reactive (bpy)Co(THF)2 species in the MOFs prevents intermolecular deactivation and stabilizes solution-inaccessible catalysts for broad-scope organic transformations. Computational, spectroscopic, and kinetic evidence further support a hitherto unknown (bpy?-)CoI(THF)2 ground state that coordinates to alkene and dihydrogen and then undergoing σ-complex-assisted metathesis to form (bpy)Co(alkyl)(H). Reductive elimination of alkane followed by alkene binding completes the catalytic cycle. MOFs thus provide a novel platform for discovering new base-metal molecular catalysts and exhibit enormous potential in sustainable chemical catalysis.
Zhang, Teng,Manna, Kuntal,Lin, Wenbin
supporting information
p. 3241 - 3249
(2016/03/19)

A new approach for bio-jet fuel generation from palm oil and limonene in the absence of hydrogen
The traditional methodology includes a carbon-chain shortening strategy to produce bio-jet fuel from lipids via a two-stage process with hydrogen. Here, we propose a new solution using a carbon-chain filling strategy to convert C10 terpene and lipids to jet fuel ranged hydrocarbons with aromatic hydrocarbon ingredients in the absence of hydrogen.
Zhang, Jingjing,Zhao, Chen
supporting information
p. 17249 - 17252
(2015/12/08)

Thermodynamically leveraged tandem catalysis for ester RC(O)O-R′ bond hydrogenolysis. scope and mechanism
Rapid and selective formal hydrogenolysis of aliphatic ester RC(O)O-R′ linkages is achieved by a tandem homogeneous metal triflate + supported palladium catalytic system. The triflate catalyzes the mildly exothermic, turnover-limiting O-R′ cleavage process, whereas the exothermic hydrogenation of the intermediate alkene further drives the overall reaction to completion.
Lohr, Tracy L.,Li, Zhi,Assary, Rajeev S.,Curtiss, Larry A.,Marks, Tobin J.
p. 3675 - 3679
(2015/06/16)

Rapid ether and alcohol C-O bond hydrogenolysis catalyzed by tandem high-valent metal triflate + supported Pd catalysts
The thermodynamically leveraged conversion of ethers and alcohols to saturated hydrocarbons is achieved efficiently with low loadings of homogeneous M(OTf)n + heterogeneous Pd tandem catalysts (M = transition metal; OTf = triflate; n = 4). For example, Hf(OTf)4 mediates rapid endothermic ether a? alcohol and alcohol a? alkene equilibria, while Pd/C catalyzes the subsequent, exothermic alkene hydrogenation. The relative C-O cleavage rates scale as 3 > 2 > 1. The reaction scope extends to efficient conversion of biomass-derived ethers, such as THF derivatives, to the corresponding alkanes.
Li, Zhi,Assary, Rajeev S.,Atesin, Abdurrahman C.,Curtiss, Larry A.,Marks, Tobin J.
supporting information
p. 104 - 107
(2014/01/23)

Synthesis and hydrogenation activity of iron dialkyl complexes with chiral bidentate phosphines
The activity of bis(phosphine) iron dialkyl complexes for the asymmetric hydrogenation of alkenes has been evaluated. High-throughput experimentation was used to identify suitable iron-phosphine combinations using the displacement of pyridine from py2Fe(CH2SiMe3)2 for precatalyst formation. Preparative-scale synthesis of a family of bis(phosphine) iron dialkyl complexes was also achieved using both ligand substitution and salt metathesis methods. Each of the isolated organometallic iron complexes was established as a tetrahedral and hence high-spin ferrous compound, as determined by M?ssbauer spectroscopy, magnetic measurements, and, in many cases, X-ray diffraction. One example containing a Josiphos-type ligand, (SL-J212-1)Fe(CH2SiMe3)2, proved more active than other isolated iron dialkyl precatalysts. Filtration experiments and the lack of observed enantioselectivity support dissociation of the phosphine ligand upon activation with dihydrogen and formation of catalytically active heterogeneous iron. The larger six-membered chelate is believed to reduce the coordination affinity of the phosphine for the iron center, enabling metal particle formation.
Hoyt, Jordan M.,Shevlin, Michael,Margulieux, Grant W.,Krska, Shane W.,Tudge, Matthew T.,Chirik, Paul J.
p. 5781 - 5790
(2015/02/19)

Photocatalytic degradation of water taste and odour compounds in the presence of polyoxometalates and TiO2: Intermediates and degradation pathways
Geosmin (GSM) and 2-methylisoborneol (MIB) are produced by several species of cyanobacteria and actinomycetes. These compounds can taint water and fish causing undesirable taste and odours. Studies have shown that GSM/MIB are resistant in standard water treatments. Polyoxometalates (POM) are efficient photocatalysts in the degradation and mineralization of a great variety of organic pollutants, presenting similar behaviour with the widely published titanium dioxide (TiO2). Photocatalytic degradation of GSM and MIB under UV-A light in the presence of a characteristic POM photocatalyst, SiW 12O404-, in aqueous solution has been studied and compared with the photodegradation by TiO2 suspensions. GSM and MIB are effectively degraded in the presence of both photocatalysts. Addition of OH radical scavengers (KBr and tertiary butyl alcohol, TBA) retards the photodegradation rates of both compounds, suggesting that photodegradation mechanism takes place via OH radicals. Intermediates identified using GC-MS in the case of GSM and MIB, are mainly identical in the presence of both photocatalysts, also suggesting a common reaction mechanism. Possible photocatalytic degradation pathway for both GSM and MIB is proposed.
Fotiou, Theodora,Triantis, Theodoros M.,Kaloudis, Triantafyllos,Papaconstantinou, Elias,Hiskia, Anastasia
p. 1 - 9
(2014/05/20)

COBALT PHOSPHINE ALKYL COMPLEXES FOR THE ASYMMETRIC HYDROGENATION OF ALKENES
Disclosed herein are manganese, iron, nickel, or cobalt compounds having a bidentate ligand and the use of these compounds for the hydrogenation of alkenes, particularly the asymmetric hydrogenation of prochiral olefins.
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(2013/11/05)

Micro and nanobubble based strategy for gas-liquid-solid multiphase reactions: Palladium-catalysed hydrogenation of carbon-carbon unsaturated bonds
An autoclave-free, gas-liquid-solid multiphase hydrogenation of carbon-carbon unsaturated bonds using hydrogen micro and nanobubbles (MNBs) is developed. The process allows the liquid phase of the reaction mixture to maintain a high concentration of hydrogen gas. Georg Thieme Verlag Stuttgart New York.
Mase, Nobuyuki,Isomura, Shogo,Toda, Mitsuo,Watanabe, Naoharu
supporting information
p. 2225 - 2228
(2013/11/06)

Solvent dependent reductive defluorination of aliphatic C-F bonds employing Sm(HMDS)2
Sm(HMDS)2 in n-hexane mediates fast cleavage of primary, secondary and tertiary alkyl fluorides in good to excellent yields. In n-hexane Sm(HMDS)2 exhibits uniquely enhanced reductive ability towards the C-F bond compared to when using THF as solvent.
Janjetovic, Mario,Tr?ff, Annika M.,Ankner, Tobias,Wettergren, Jenny,Hilmersson, G?ran
supporting information
p. 1826 - 1828
(2013/03/29)

NOVEL ALICYCLIC ALCOHOL
Provided is an alicyclic alcohol compound which can be used as a raw material for a compound perfume, and which has excellent floral-green like aromas which are crisp and fresh; also provided are a manufacturing method for the same, and a perfume composition which contains the alicyclic alcohol compound. An alicyclic alcohol compound having a specified structure represented by chemical formula (1) has excellent floral-green-like aromas which are crisp and fresh; and a method for manufacturing the alicyclic alcohol compound represented by chemical formula (1) by reacting, in the presence of hydrogen fluoride, 1-isopropyl-4-methylcyclohexene and carbon monoxide, reacting the resulting 4-isopropyl-1-methylcyclohexane carboxylic acid fluoride with alcohol, and, after having acquired a cyclohexane carbonyl compound, reducing the cyclohexane carbonyl compound.
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(2013/11/19)

Selective reduction of dienes/polyenes using sodium borohydride/catalytic ruthenium(III) in various liquid amide aqueous mixtures
An efficient method to effect selective reduction of several structurally diverse dienes and an unsymmetrical triene is reported. The reduction is facile at 0 °C in a liquid amide aqueous solution containing sodium borohydride in the presence of 15 mol % ruthenium(III) chloride. The chemoselectivity of the reaction is controlled by proper choice of the liquid amide solvent.
Babler, James H.,Ziemke, David W.,Hamer, Robert M.
p. 1754 - 1757
(2013/04/10)

Application of a versatile nanoparticle stabilizer in phase transfer and catalysis
Gold and rhodium nanoparticles stabilized by a cationic polymer can be readily modified by anion exchange to afford nanoparticles that may be dispersed in a wide range of organic solvents and ionic liquids. The catalytic activity of the Rh nanoparticle dispersions have been evaluated in the selective hydrogenation of limonene and the nature of the solvent has been shown to play a critical role.
Biondi, Ilaria,Laporte, Vincent,Dyson, Paul J.
p. 721 - 726
(2013/01/14)

Application of a versatile nanoparticle stabilizer in phase transfer and catalysis
Gold and rhodium nanoparticles stabilized by a cationic polymer can be readily modified by anion exchange to afford nanoparticles that may be dispersed in a wide range of organic solvents and ionic liquids. The catalytic activity of the Rh nanoparticle dispersions have been evaluated in the selective hydrogenation of limonene and the nature of the solvent has been shown to play a critical role.
Biondi, Ilaria,Laporte, Vincent,Dyson, Paul J.
p. 721 - 726
(2014/01/17)

Preparation and utilization of perillyl acetate
Perillyl acetate is a fragrance compound that was prepared by the reaction of β-pinenoxide with acetic anhydride and using acetic acid as an acid catalyst. Several selected catalysts were tested (homogenous: phosphoric acid, boric acid, acetic acid, and citric acid; heterogeneous: zeolite USY, SSA, and montmorillonite K-10) and the reaction conditions optimized for this reaction. The yield 78.7 % of perillyl acetate was obtained. Mayol (4- isopropylcyclohexylmethanol), a valuable fragrance compound, was further obtained by a two-step synthesis from perillyl acetate. Firstly, perillyl acetate was saponified to perillyl alcohol. The yield of alcohol was 94.4 %. The last step of the entire preparation was the hydrogenation of perillyl alcohol to Mayol. The yield of the desired product of this reaction was 94.6 %. Springer Science+Business Media B.V. 2012.
?tekrová, Martina,Paterová-Dudková, Iva,Vysko?ilová-Leitmannová, Eli?ka,?erveny, Libor
p. 2075 - 2084
(2013/02/22)

Chemoselective hydrogenation of the olefinic bonds using a palladium/magnesium-lanthanum mixed oxide catalyst
A palladium/magnesium-lanthanum mixed oxide catalyst is found to be an efficient heterogeneous catalyst for the chemoselective hydrogenation of olefinic double bonds in the presence of various functional groups. The catalyst was recovered by centrifugation and reused for several cycles with consistent activity and selectivity. Copyright
Kantam, Mannepalli Lakshmi,Kishore, Ramineni,Yadav, Jagjit,Sudhakar, Medak,Venugopal, Akula
supporting information; experimental part
p. 663 - 669
(2012/04/23)

Thiotolerant Ir/SiO2-Al2O3 bifunctional catalysts: Effect of metal-acid site balance on tetralin hydroconversion
The hydroconversion of tetralin over iridium nanoparticles supported on amorphous silica-alumina (ASA) has been investigated in a continuous high-pressure gas-phase micro-reactor in the presence of H2S. In order to tune the Ir particle size, the bifunctional Ir/ASA catalysts have been submitted to sintering treatments. The samples have been characterized by HRTEM and XPS. From careful analysis of tetralin conversion products by comprehensive two-dimensional gas chromatography (GC×GC-MS) and NMR, compound families have been unambiguously distinguished. Hydrogenation, dehydrogenation, (saturated and aromatic) ring-contraction products, and (saturated and aromatic) one-ring-opening products are formed, without significant cracking. The catalysts exhibit stable activity in the presence of sulfur. As the mean particle size increases from 1.5 to 8 nm, the ring-opening/contraction selectivity increases dramatically. This effect is related to an increase of the acid/metal site ratio.
Nassreddine, Salim,Massin, Laurence,Aouine, Mimoun,Geantet, Christophe,Piccolo, Laurent
scheme or table
p. 253 - 265
(2011/04/22)

A convenient methodology for the chemoselective reduction of a wide variety of functionalized alkenes
An efficient method to effect chemoselective reduction of alkenes (including trisubstituted olefins) possessing various sensitive and/or reducible groups such as acetals, allylic alcohols, benzyl ethers, epoxides, esters, halides, nitriles, and sulfones is reported. The reduction is facile at 0 °C in aqueous N,N-dimethylacetamide containing sodium borohydride in the presence of 15 mol % ruthenium(III) chloride. Regioselective reduction of dienes is also feasible if the double bonds are sufficiently different in their structural environment.
Babler, James H.,White, Nicholas A.
experimental part
p. 439 - 441
(2010/03/04)

Catalytic activity of the VIII group metals in the hydrogenation and isomerization of α- And β-pinenes
The kinetic regularities of the liquid-phase hydrogenation and isomerization of α- and β-pinenes over the Pd/C, Ru/C, Rh/C, Pt/C, and Ir/C catalysts were studied at temperatures ranging from 20 to 100 °C and at hydrogen pressures of 1-11 bar using n-octane as the solvent. The hydrogenation and isomerization of α- and β-pinenes occur simultaneously on the Ru/C, Rh/C, Pt/C, and Ir/C catalysts, and the reaction mixture contains the products of double bond hydrogenation, viz., cis- and trans-pinanes. The Ru, Rh, and Pd metals have a higher catalytic activity in β-pinene isomerization than Ir and Pt. Among the VIII Group metals studied, the Pd-based catalyst has the highest catalytic activity in double bond isomerization of α- and β-pinenes. The general scheme of the mechanism of hydrogenation and isomerization of α- and β-pinenes on the Pd/C catalyst was proposed.
Deliy,Simakova
body text
p. 2056 - 2064
(2010/05/02)

A novel reduction reaction for the conversion of aldehydes, ketones and primary, secondary and tertiary alcohols into their corresponding alkanes
A novel one-pot reaction has been developed for the reduction of aldehydes, ketones and primary, secondary and tertiary alcohols into their corresponding alkyl function. This is also the first reported method which can efficiently reduce primary, secondary, or tertiary alcohols, without affecting carbon-carbon double bonds, into their corresponding alkyl function in high yields. The reduction utilises either diethylsilane or n-butylsilane as the reducing agent in the presence of the Lewis acid catalyst tris(pentafluorophenyl)borane.
Nimmagadda, Rama D.,McRae, Christopher
p. 5755 - 5758
(2007/10/03)

Stereoselective synthesis of (6R)- and (6S)-diosphenol and Ψ-diosphenol
Methods are discussed for the stereoselective synthesis of the (R)-and (S)-enantiomers of the diosphenols (5)-(8) by utilizing the commercially available stereoisomers (9), (12), (23) and (25) of carvone and limonene, respectively, as chiral starting materials.
Schneider, David F,Viljoen, Murray S
p. 5307 - 5315
(2007/10/03)

Reduction of Carbonyl Compounds to Hydrocarbons by Catalytic Hydrogenation: A Novel One-Pot Method Using Pt/K-10 Montmorillonite Catalyst
Catalytic hydrogenation by a bifunctional 5 percent Pt/K-10 catalyst, which is easy to prepare, was found to be an effective method to reduce C=O groups to CH2 in carbonyl compounds. This one-pot method was applied in a wide variety of ketones. A suggested mechanism of the reaction is also presented.
Toeroek, Bela,London, Gabor,Bartok, Mihaly
p. 631 - 632
(2007/10/03)

Electroreductive cyclisation of unsaturated halides catalysed by nickel macrocyclic complexes
The indirect electroreduction of unsaturated aliphatic halides using Ni(II) complexes as electron-transfer mediators is achieved in N,N'-dimethylformamide by constant current electrolysis between a cathode and a sacrificial anode in a diaphragmless cell. Cyclic compounds are obtained in low to high yields in conditions that avoid the usual preparation using organotin reagents.
Dunì?ach,Esteves,Freitas,Medeiros,Olivero
p. 8693 - 8696
(2007/10/03)

Photo-assisted hydrogen transfer from alcohol to limonene catalyzed by [Rh6(CO)16]
Partial hydrogenation of the exo-olefinic bond in limonene to carvomenthene proceeds smoothly by photocatalytic hydrogen transfer from 2-propanol using [Rh6(CO)16] as a catalyst under UV-irradiation in the presence of acetone. Hydrogen gas evolves after the formation of carvomenthene has been completed. 1-Hydroxy-1-methylethyl radical formed in the reaction of photochemically excited acetone with 2-propanol serves both as an activator for the catalyst and as a hydrogen source.
Yanagawa, Akihisa,Hatae, Tomomi,Yada, Satoru,Sugimori, Akira,Takagi, Yuzuru
p. 899 - 900
(2007/10/03)

Ni-Cu/Al2O3 containing O.1percent CeO2: A New Catalyst for Dehydrogenation of Alcohols
A highly active and selective catalyst containing 10percent Ni-Cu (atomic ratio 7 : 3) supported on alumina and promoted with 0.1percent cerium oxide was developed for dehydrogenation of secondary alcohols into corresponding ketones in vapour phase.
Singh, Satendra,Dev, Sukh
p. 463 - 468
(2007/10/02)

Radical Cations of Cyclohexanes Alkyl-substituted on One Carbon: An ESR Study of the Jahn-Teller Distorted HOMO of Cyclohexane
Cation radicals of cyclohexanes alkyl-substituted on one carbon have been stabilized in perfluoromethylcyclohexane and other halocarbon matrices at 4.2 K and studied by means of ESR spectroscopy.It was found that all have an electronic ground state resembling the 2Ag state of the cyclohexane cation, one of the possible states following a Jahn-Teller distortion of the D3d cyclohexane chair structure.The cations can be classified into two groups depending on the substituted alkyl group.To the first group belong the cations with a methyl group or a primary carbon (ethyl, n-propyl or isobutyl group) attached to the ring.The disubstituted cyclohexane cations of 1,1-dimethylcyclohexane and 1-methyl-1-ethylcyclohexane were also found to have a similar structure.The ESR spectra are characterized by a 1:2:1 three-line pattern with the hyperfine (hf) splitting due to two magnetically equivalent equatorial ring hydrogens.The magnitude of the splitting was found to depend on the size and number of substituents, ranging from 74 G (methylcyclohexane.+) to 55 G (isobutylcyclohexane.+).An additional doublet, 17-34 G, due to a hydrogen on the substituent could be detected in certain cases.Such hydrogens are axial with one of the elongated C-C bonds in the ring structure which contains a relatively large fraction of the unpaired electron.It follows that the substituents are located asymmetrically with respect to an ag-like SOMO in the ring.In the second group a secondary or tertiary carbon connects the substituent to the ring, such as an isopropyl or tert-butyl group.The largest hf splittings are ca. 30 G in magnitude, due to certain hydrogens on the substituent which are axial with respect to the cyclohexyl bond.It follows that an ag-like SOMO in the ring here is symmetrically arranged with respect to the position of the substituent.Hyperconjugation is the dominating mechanism for the spin transfer in all cations reported in this study.
Shiotani, Masaru,Lindgren, Mikael,Ohta, Nobuaki,Ichikawa, Takahisa
p. 711 - 719
(2007/10/02)

OXYGENATED DERIVATIVES OF MENTHATRIENE IN PARSLEY LEAVES
The analysis of aroma volatiles of parsley revealed the presence of two novel oxygenated p-mentha-1,3,8-tiene derivatives, the amounts of which increase during processing of plant material and deteriorate the typical fresh aroma.The two derivatives, which could be synthesized by means of a dye sensitized photooxygenation reaction, were identified as 1-methyl-4(methylethenyl)-2,3-dioxabicyclooct-5-ene and 4-methyl-7-(methylethenyl)-3,8-dioxatricyclo2-4>octane.Key Word Index - Petroselinum crispum; Umbelliferae; parsley; aroma volatiles; p-mentha-1,3,8-triene; dioxetane; 1-methyl-4-(methylethenyl)-2,3-dioxabicyclooct-5-ene; diepoxide; 4-methyl-7-(methylethenyl)-3,8-dioxatricyclo2-4>octane.
Nitz, Siegfried,Kollmannsberger, Hubert,Spraul, Martin H.,Drawert, Friedrich
p. 3051 - 3054
(2007/10/02)

CATALYTIC HYDROGENATION OF OLEFINS IN BIPHASIC WATER-LIQUID SYSTEM
Cyclic and linear olefins and polyenes with or without functional groups are hydrogenated under very mild reaction conditions.Emphasis is put on the advantages of this method which requires no solvent and a water-soluble non air-sensitive catalyst.
Larpent, Chantal,Dabard, Renee,Patin, Henri
p. 2507 - 2510
(2007/10/02)

TOTAL SYNTHESIS OF (-)-PERIPLANONE-B, NATURAL MAJOR SEX-EXCITANT PHEROMONE OF THE AMERICAN COCKROACH, PERIPLANETA AMERICANA
The total synthesis of (-)-periplanone-B 1, the major sex excitant and attractant pheromone of the American cockroach was accomplished starting from (+)-dihydrolimonene 2.Intramolecular alkylation of the substituted α-phenylthioacrylate 10 gave rise to the (E)-cyclodecene 11.Second key reaction was the reductive elimination of vicinal phenylthiobenzoate 14 to provide the cojugated diene 15.Overall yield of 1 through 28 steps was 0.5 percent.
Kitahara, Takeshi,Mori, Masataka,Mori, Kenji
p. 2689 - 2700
(2007/10/02)

A RADICAL DEOXIGENATION OF SECONDARY ALCOHOLS TO HYDROCARBONS BY USE OF TRIBUTYLTIN HYDRIDE
Secondary alcohols 1 reacted with 2,2'-dibenzothiazolyldisulfide in the presence of tributylphosphine to give corresponding sulfides 2 in good yields.Sulfides 2 were subsequently desulfurized to hydrocarbons 3 with tributyltin hydride in radical conditions.
Watanabe, Yoshihiko,Araki, Takumi,Ueno, Yoshio,Endo, Takeshi
p. 5385 - 5388
(2007/10/02)

DISPROPORTIONATION OF HYDROGEN IN 3-CARENE
The disproportionation of hydrogen in 3-carene takes place with the formation of compounds of the 1,1,4-trimethylcycloheptane series.The proposed reaction mechanism involves dehydration of the 2-carene to 2,4-caradiene, which exists in a rapid tautomeric equilibrium with 3,7,7-trimethyl-1,3,5-cycloheptatriene.This gives rise to the appearance of compounds with a seven-membered ring in the reaction product.
Manukov, E. N.,Chuiko, V. A.,Vyglazov, O. G.
p. 257 - 262
(2007/10/02)

Action des metaux sur les esters carboxyliques en presence d'hexamethylphosphortriamide: une methode simple et efficace de reduction des alcools en alcanes
Carboxylic acids, alcohols (R'OH), and alkanes (R'H) are the main products of the reduction of carboxylic esters (RCO2R') by sodium in hexamethylphosphoric triamide (HMPA).Alkanes are preferentially formed from the carboxylic esters of hindered alcohols.The alkane content, however, is lowered when there is less steric hindrance on the carboxylic group, and increased when tert-butanol is introduced into the reaction mixture.The reduction of esters in HMPA has been compared to the reduction in alkylamines.The alkane is produced mainly by the decomposition of a radical anion intermediate which can be solvated by HMPA.The alcohol is the result of several possible bimolecular nucleophilic reactions; however, unimolecular and bimolecular processes are involved in the production of the carboxylic acid.
Deshayes, Henri,Pete, Jean-Pierre
p. 2063 - 2072
(2007/10/02)

FORMATION OF SULPHUR COMPOUNDS IN THE HYDRODENITROGENATION OF 2-METHYLQUINOLINE, 2-METHYLPIPERIDINE, INDOLE, AND ISOQUINOLINE ON A NICKEL-TUNGSTEN CATALYST IN THE PRESENCE OF HYDROGEN SULPHIDE
2-Methylquinoline, 2-methylpiperidine, indole, and isoquinoline were subjected to hydrodenitrogenation (HDN) on a sulphidized nickel-tungsten catalyst in an autoclave at 300 and 350 deg C using pure hydrogen or a hydrogen-hydrogen sulphide mixture.The neutral fraction from the HDN of 2-methylquinoline and 2-methylpiperidine contained 40 and 90percent sulphur compounds, respectively.The presence of hydrogen sulphide in the HDN of isoquinoline resulted in an enhanced fraction of the neutral moiety.A reaction mechanism is suggested for the HDN of 2-methylquinoline and 2-methylpiperidine in the presence of hydrogen sulphide, in which the latter contributes to the higher degree of conversion due to the formation of corresponding sulphur compounds.
Cerny, Mirko,Trka, Antonin
p. 3413 - 3420
(2007/10/02)

HYDROGENOLYSE EN PHASE LIQUIDE SUR Pd/C DES EPOXYDES DU CARVOMENTHENE ET DU LIMONENE
Hydrogenolysis over Pd/C of cis and trans epoxides of carvomenthene and limonene give a mixture of hydrocarbons, secondary and tertiary alcohols, and ketones in proportions dependent upon the nature of the starting material.In the limonene epoxides, the extracyclic double bond plays an important role in the opening of the oxirane ring through a common unsaturated tertiary alcohol intermediate by double bond migration, hydrogenation of which leads to the products.For the carvomenthene epoxides the results are similar to those found in the 4-t-butyl series with competition between cis addition and trans addition of hydrogen.The presence of the isopropenyl group leads to slower reaction rates in comparison with t-butyl analogues.
Accrombessi, G.,Geneste, P.,Olive, J.-L.,Pavia, A. A.
p. 3135 - 3140
(2007/10/02)