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One-step synthesis of Pt@ZIF-8 catalyst for the selective hydrogenation of 1,4-butynediol to 1,4-butenediol
A catalyst consisting of platinum nanoparticles on a ZIF-8 support (Pt@ZIF-8) was synthesized in a straightforward one-step procedure, by adding a nanostructured platinum sol during the formation of ZIF-8 at room temperature. Pt@ZIF-8 was highly porous an
Li, Chuang,Zhang, Mingming,Di, Xin,Yin, Dongdong,Li, Wenzhen,Liang, Changhai
p. 1555 - 1561
(2016)
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PVP-Pd@ZIF-8 as highly efficient and stable catalysts for selective hydrogenation of 1,4-butynediol
Cubic Pd nanoparticles were rapidly encapsulated in ZIF-8 through a PVP-assisted synthetic method at room temperature. The obtained PVP-Pd@ZIF-8 exhibited high activity and stability for hydrogenation of 1,4-butynediol, with excellent selectivity to 1,4-b
Zhang, Mingming,Yang, Yuebin,Li, Chuang,Liu, Qian,Williams, Christopher T.,Liang, Changhai
p. 329 - 332
(2014)
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An excellent nickel boride catalyst for the cis-selective semihydrogenation of acetylenes
Internal alkynes were hydrogenated quantitatively to the corresponding cis-alkenes over nickel boride (Ni2B), prepared on borohydride exchange resin (BER) in methanol under hydrogen atmosphere. Further hydrogenation was very slow under the reaction conditions, and pure cis-alkenes were conveniently isolated in excellent yields. Hydroxy and ester functional groups did not interfere with the semihydrogenation.
Choi, Jaesung,Yoon, Nung Min
p. 1057 - 1060
(1996)
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Parahydrogen-Induced Polarization Relayed via Proton Exchange
The hyperpolarization of nuclear spins is a game-changing technology that enables hitherto inaccessible applications for magnetic resonance in chemistry and biomedicine. Despite significant advances and discoveries in the past, however, the quest to establish efficient and effective hyperpolarization methods continues. Here, we describe a new method that combines the advantages of direct parahydrogenation, high polarization (P), fast reaction, and low cost with the broad applicability of polarization transfer via proton exchange. We identified the system propargyl alcohol + pH2 → allyl alcohol to yield 1H polarization in excess of P ≈ 13% by using only 50% enriched pH2 at a pressure of ≈1 bar. The polarization was then successfully relayed via proton exchange from allyl alcohol to various target molecules. The polarizations of water and alcohols (as target molecules) approached P ≈ 1% even at high molar concentrations of 100 mM. Lactate, glucose, and pyruvic acid were also polarized, but to a lesser extent. Several potential improvements of the methodology are discussed. Thus, the parahydrogen-induced hyperpolarization relayed via proton exchange (PHIP-X) is a promising approach to polarize numerous molecules which participate in proton exchange and support new applications for magnetic resonance.
Them, Kolja,Ellermann, Frowin,Pravdivtsev, Andrey N.,Salnikov, Oleg G.,Skovpin, Ivan V.,Koptyug, Igor V.,Herges, Rainer,H?vener, Jan-Bernd
supporting information
p. 13694 - 13700
(2021/09/07)

Continuous Flow Z-Stereoselective Olefin Metathesis: Development and Applications in the Synthesis of Pheromones and Macrocyclic Odorant Molecules**
The first continuous flow Z-selective olefin metathesis process is reported. Key to realizing this process was the adequate choice of stereoselective catalysts combined with the design of an appropriate continuous reactor setup. The designed continuous process permits various self-, cross- and macro-ring-closing-metathesis reactions, delivering products in high selectivity and short residence times. This technique is exemplified by direct application to the preparation of a range of pheromones and macrocyclic odorant molecules and culminates in a telescoped Z-selective cross-metathesis/ Dieckmann cyclisation sequence to access (Z)-Civetone, incorporating a serial array of continually stirred tank reactors.
Browne, Duncan L.,Colombel-Rouen, Sophie,Crévisy, Christophe,Curbet, Idriss,Mauduit, Marc,McBride, Tom,Morvan, Jennifer,Roisnel, Thierry
supporting information
p. 19685 - 19690
(2021/08/06)

Fourth subgroup metal complex with rigid annular bridging structure and application of fourth subgroup metal complex
The invention belongs to the technical field of olefin polymerization catalysts, and particularly relates to a fourth subgroup metal complex with a rigid annular bridging structure and an application of the fourth subgroup metal complex. The fourth subgroup metal complex provided by the invention has a structure represented by a formula (A) or a formula (B), X is halogen or alkyl; and M is titanium, zirconium or hafnium. On the basis of a non-metallocene catalyst, a bridging structure in catalyst molecules is improved and upgraded, and a brand-new metal complex with excellent catalytic performance and good high-temperature tolerance is designed; when the fourth subgroup metal complex is used as a main catalyst to catalyze olefin polymerization reaction, under the activation action of a small amount of mixed cocatalyst, the fourth subgroup metal complex can efficiently catalyze the copolymerization reaction of ethylene and alpha-olefin to obtain polyolefin with high molecular weight and high comonomer insertion rate.
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Paragraph 0058; 0061; 0066

(2021/06/23)

Preparation method of N-(4-methylpyridine-3-yl) methyl carbamate
The invention relates to the technical field of preparation methods of N-(4-methylpyridine-3-yl) methyl carbamate, and discloses preparation of potassium tert-butoxide and preparation of the potassium tert-butoxide by using potassium methoxide. According to the preparation method of the N-(4-methylpyridine-3-yl) methyl carbamate, a user uses the potassium methoxide to prepare the potassium tert-butoxide, so that the content of the potassium tert-butoxide is higher, the potassium tert-butoxide and the potassium methoxide are very similar in properties and functions, so that the cost is saved, the method for extracting a THT solvent by using 1, 4-dichlorobutene as a raw material is simple, and the method has the advantages that the use amount of the catalyst is small, the condition is mild, the extraction purity is high, so that the cost is reduced again; and the N-(4-methylpyridine-3-yl) methyl carbamate is obtained by catalyzing two high-purity raw materials through the catalyst carbonic acid diester and stirring, so that the preparation efficiency is improved, the purity of the prepared N-(4-methylpyridine-3-yl) methyl carbamate is improved, the over-high preparation cost of the N-(4-methylpyridine-3-yl) methyl carbamate is avoided, and the use of the user is facilitated.
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Paragraph 0020; 0022; 0025; 0030; 0032; 0035; 0040; 0042

(2021/06/02)

Dehydrogenative alcohol coupling and one-pot cross metathesis/dehydrogenative coupling reactions of alcohols using Hoveyda-Grubbs catalysts
In this study,in situformed ruthenium hydride species that were generated from Grubbs type catalysts are used as efficient catalysts for dehydrogenative alcohol coupling and sequential cross-metathesis/dehydrogenative coupling reactions. The selectivity of Grubbs first generation catalysts (G1) in dehydrogenative alcohol coupling reactions can be tuned for the ester formation in the presence of weak bases, while the selectivity can be switched to the β-alkylated alcohol formation using strong bases. The performance of Hoveyda-Grubbs 2nd generation catalyst (HG2) was improved in the presence of tricyclohexylphosphine for the selective synthesis of ester derivatives with weak and strong bases in quantitative yields. Allyl alcohol was used as self and cross-metathesis substrate for the HG2 catalyzed sequential cross-metathesis/dehydrogenative alcohol coupling reactions to obtain γ-butyrolactone and long-chain ester derivatives in quantitative yields.
?zer, Halenur,Arslan, Dilan,?ztürk, Bengi ?zgün
p. 5992 - 6000
(2021/04/12)

Highly selective semi-hydrogenation of alkynes with a Pd nanocatalyst modified with sulfide-based solid-phase ligands
Soluble small molecular/polymeric ligands are often used in Pd-catalyzed semi-hydrogenation of alkynes as an efficient strategy to improve the selectivity of targeted alkene products. The use of soluble ligands requires their thorough removal from the reaction products, which adds significant extra costs. In the paper, commercially available, inexpensive, metallic sulfide-based solid-phase ligands (SPL8-4 and SPL8-6) are demonstrated as simple yet high-performance insoluble ligands for a heterogeneous Pd nanocatalyst (Pd@CaCO3) toward the semi-hydrogenation of alkynes. Based on the reactions with a range of terminal and internal alkyne substrates, the use of the solid-phase ligands has been shown to markedly enhance the selectivity of the desired alkene products by efficiently suppressing over-hydrogenation and isomerization side reactions, even during the long extension of the reactions following full substrate conversion. A proper increase in the dosage or a reduction in the average size of the solid-phase ligands enhances such effects. With their insoluble nature, the solid-phase ligands have the distinct advantage in their simple, convenient recycling and reuse while without contaminating the products. A ten-cycle reusability test with the SPL8-4/Pd@CaCO3 catalyst system confirms its well-maintained activity and selectivity over repeated uses. A mechanistic study with x-ray photoelectron spectroscopy indicates that the solid-phase ligands have electronic interactions with Pd in the supported catalyst, contributing to inhibit the binding and further reaction of the alkene products. This is the first demonstration of solid-phase ligands for highly selective semi-hydrogenation of alkynes, which show strong promise for commercial applications.
Huang, Lingqi,Hu, Kecheng,Ye, Ganggang,Ye, Zhibin
(2021/03/30)

Piperazine-promoted gold-catalyzed hydrogenation: The influence of capping ligands
Gold nanoparticles (NPs) combined with Lewis bases, such as piperazine, were found to perform selective hydrogenation reactions via the heterolytic cleavage of H2. Since gold nanoparticles can be prepared by many different methodologies and using different capping ligands, in this study, we investigated the influence of capping ligands adsorbed on gold surfaces on the formation of the gold-ligand interface. Citrate (Citr), poly(vinyl alcohol) (PVA), polyvinylpyrrolidone (PVP), and oleylamine (Oley)-stabilized Au NPs were not activated by piperazine for the hydrogenation of alkynes, but the catalytic activity was greatly enhanced after removing the capping ligands from the gold surface by calcination at 400 °C and the subsequent adsorption of piperazine. Therefore, the capping ligand can limit the catalytic activity if not carefully removed, demonstrating the need of a cleaner surface for a ligand-metal cooperative effect in the activation of H2 for selective semihydrogenation of various alkynes under mild reaction conditions.
Barbosa, Eduardo C. M.,Camargo, Pedro H. C.,Fiorio, Jhonatan L.,Hashmi, A. Stephen K.,Kikuchi, Danielle K.,Rossi, Liane M.,Rudolph, Matthias
p. 1996 - 2003
(2020/04/22)

A Schiff Base Modified Pd Catalyst for Selective Hydrogenation of 2-Butyne-1,4-diol to 2-Butene-1,4-diol
Abstract: Schiff-base modified Pd nanoparticles (NPs) supported on silica with an average size of ca. 2?nm have been synthesized via a one-pot aldimine condensation followed by impregnation-reduction of a palladium precursor, and the sample exhibits an excellent catalytic activity and selectivity in hydrogenation of 2-butyne-1,4-diol (BYD) to 2-butene-1,4-diol (BED). Under the mild reaction conditions (50?°C, 2?MPa H2, and 4?h) and additive-free, 95.2% BYD conversion has been achieved with ca. 100% BED selectivity over the Pd/SiO2–Schiff catalyst, and the Pd/SiO2–Schiff catalyst presents an excellent catalytic stability. The above results are much better than that of commercial Lindlar catalyst, and the improved catalytic performance is attributed to the strong metal–support interaction derived from the coordination of nitrogen sites (Schiff-base) to Pd NPs, based on catalyst characterization results. Graphic Abstract: Featured by additive-free and high selectivity, hydrogenation of 2-butyne-1,4-diol to 2-butene-1,4-diol over the Pd/SiO2–Schiff catalyst has been developed, aiming for green production of fine chemicals.[Figure not available: see fulltext.]
Li, Haomeng,Wang, Xinkui,Chen, Xiao,Li, Chuang,Wang, Min,Yi, Yanhui,Ji, Min,Wang, Huilong,Shao, Zhengfeng,Liang, Changhai
p. 2150 - 2157
(2020/02/13)

Water soluble homogeneous catalysts that are recoverable by phase selectivity and host-guest interactions
A chemical reaction is catalyzed in an organic solvent using a water soluble N-heterocyclic carbene homogeneous catalyst to form a reaction mixture. An aqueous phase in the reaction mixture. A solvent in which the catalyst is insoluble is added to the reaction mixture, causing the catalyst to migrate to the aqueous phase to form a catalyst-laden aqueous phase. The catalyst is extracted from the catalyst-laden aqueous phase.
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(2020/08/30)

An efficient approach for the synthesis of novel methyl sulfones in acetic acid medium and evaluation of antimicrobial activity
A series of nine methyl sulphones (3a-3i) starting from the aldehydes (1a-1i) were synthesized in two consecutive steps. In the first step, preparation of allyl alcohols (2a-2i) from their corresponding aldehydes by the reaction of sodium borohydride in methanol at room temperature is reported. Finally, methyl sulphones are synthesized by condensing sodium methyl sulfinates with allyl alcohols in the presence of BF3.Et2O in acetic acid medium at room temperature for about 2-3 h. The reaction conditions are simple, yields are high (85%-95%), and the products were obtained with good purity. All the synthesized compounds were characterized by their 1H, 13C NMR, and mass spectral analysis. All the title compounds were screened for antimicrobial activity. Among the compounds tested, the compound 3f has inhibited both Gram positive and Gram negative bacteria effectively and compound 3i has shown potent antifungal activity. These promising components may help to develop more potent drugs in the near future for the treatment of bacterial and fungal infections.
Bollikolla, Hari Babu,Dasireddy, Chandra Rao,Kotra, Vijay,Ravi Kumar, Gollapudi,Varala, Ravi
p. 1386 - 1394
(2020/11/20)

Olefin reaction in the catalyst and the olefin production
PROBLEM TO BE SOLVED: To provide a catalyst for obtaining an olefin in high selectivity with a vicinal diol as a raw material.SOLUTION: A catalyst for olefination reaction for use in a reaction to produce an olefin by a reaction of a polyol, having two adjacent carbon atoms each having a hydroxy group, with hydrogen comprises: a carrier; at least one oxide selected from the group consisting of oxides of the group 6 elements and oxides of the group 7 elements supported on the carrier; and at least one metal selected from the group consisting of silver, iridium, and gold supported on the carrier.SELECTED DRAWING: None
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Paragraph 0145-0146; 0149

(2020/10/31)

Method for preparing olefin by catalyzing dehydration and deoxidation of polyhydroxy compound with organic molybdenum
The invention discloses a method for preparing olefin by catalyzing dehydration and deoxidation of a polyhydroxy compound with organic molybdenum. The method comprises the following steps: reacting apolyhydroxy compound-containing raw material in the presence of an organic molybdenum-based catalyst to obtain olefin. According to the method, compounds containing nitrogen, sulfur, oxygen, phosphorus and other monodentate and polydentate coordination groups are used as organic ligands, and a series of organic molybdenum catalysts are prepared and used for catalyzing a deoxidation and dehydrationreaction of vicinal diol. The invention provides a cheap non-noble metal molybdenum-based catalyst, wherein the cost is greatly reduced.
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Paragraph 0122; 0124; 0129; 0131; 0134-0135

(2020/07/02)

Towards Sustainable Catalysis – Highly Efficient Olefin Metathesis in Protic Media Using Phase Labelled Cyclic Alkyl Amino Carbene (CAAC) Ruthenium Catalysts
New generations of Hoveyda and bis-carbene type of ruthenium-based olefin metathesis catalysts (10 and 12), containing cationic cyclic alkyl amino carbene (CAAC) ligands, have been synthetized. The catalysts show exceptional stability and activity in environmentally benign, protic media. Various olefin metatheses reactions of OH functionalized feedstock (e. g. RCM, ROMP CM) can be carried out at as low as 0.05 mol % catalyst loading in methanol, isopropanol, water or methanol/water solvent mixture, accomplishing the lowest applied catalyst loading reported so far in these media. The facile olefin metathesis of renewable feedstocks including phospholipids (23) and vegetable oils (20) in protic media has also been demonstrated.
Nagyházi, Márton,Turczel, Gábor,Balla, áron,Szálas, Gábor,Tóth, Imre,Gál, Gyula Tamás,Petra, Bombicz,Anastas, Paul T.,Tuba, Róbert
p. 1953 - 1957
(2020/02/15)

The influence of nickel loading on the structure and performance of a Ni-Al2O3 catalyst for the hydrogenation of 1,4-butynediol to produce 1,4-butenediol
In combination with a planetary ball-milling machine, a Ni-Al2O3 catalyst was prepared by a mechanochemical method. The effect of Ni loading on the crystal structure, reduction characteristics, and hydrogenation performance of the Ni-Al2O3 catalyst was investigated. The prepared catalysts were characterized using EDX, XRD, H2-TPR, BET, TEM and NH3-TPD methods. The results of the XRD characterization showed that the peak intensity of the active Ni component increased with an increase in the Ni content. The ratio of the measured Ni content to the theoretical Ni content of the MC25percent and MC30percent samples exceeded 1.1. As the Ni addition was increased up to 10percent, the sample consisted of uniform spherical particles, which could provide more contact surfaces. The medium acid peak temperature shifts towards the high temperature direction as the Ni loading increased from 5percent to 20percent, and then (>20percent) decreased to a lower temperature. The corresponding peak area firstly increased and then decreased, presenting a visual representation of changes in the number of acid centers on the catalyst. Evaluation of the results showed that the MC20percent catalyst presented a large specific surface area of 279 m2 g-1, and it showed good hydrogenation performance, with a BYD conversion of 25.0percent, BED selectivity of 89.3percent, and BED yield of 22.3percent.
Gao, Xianlong,Mo, Wenlong,Ma, Fengyun,Fan, Xing
p. 7683 - 7689
(2020/07/25)

Bimetallic Synergy Effects of Phyllosilicate-Derived NiCu@SiO2 Catalysts for 1,4-Butynediol Direct Hydrogenation to 1,4-Butanediol
Hydrogenation of 1,4-butynediol (BYD) to 1,4-butanediol (BDO) is a two-step process, with an initial hydrogenation of BYD to 1,4-butenediol (BED) and the subsequent hydrogenation of BED to BDO. However, the BYD hydrogenation also involves many side reactions originated from the isomerization of BED. In order to inhibit the isomerization pathways, phyllosilicate-derived bimetallic NiCu@SiO2 catalysts have been developed for efficient C≡C/C=C hydrogenation in this work. Due to the formation of phyllosilicate matrix and highly dispersed metal nanoparticles, NiCu@SiO2 showed total BYD conversion with extremely high BDO selectivity compared to a conventional impregnated Ni/SiO2 catalyst. A remarkable result of NiCu@SiO2 catalysts is that a new type of bimetallic catalytic sites responsible for the high hydrogenation activity can be differentiated from the Ni phyllosilicate matrix by the induction of Cu species, and these neighboring bimetallic sites with the help of weak acid phyllosilicate interface, can realize to stabilize the activated BED species (allyl alcohol form) adsorbed on the cooperative active sites, thus to avoid its isomerization to aldehyde form and unexpected C=O hydrogenolysis. Consequently, it enhanced the selectivity to the diol products BDO significantly. Owing to the benign improvement of three center synergy effect, 9Ni1Cu@SiO2 possesses the optimum BYD direct hydrogenation ability with a rarely reported high selectivity of 90.5–94.5 % at 50 °C and 1 MPa.
Wang, Changzhen,Tian, Yani,Wu, Ruifang,Li, Haitao,Yao, Benzhen,Zhao, Yongxiang,Xiao, Tiancun
p. 4777 - 4787
(2019/08/26)

Ammonium-tagged ruthenium-based catalysts for olefin metathesis in aqueous media under ultrasound and microwave irradiation
The influence of microwave and ultrasonic irradiation on the performance of ammonium-tagged Ru-based catalysts in olefin metathesis transformations in aqueous media was studied. Differences in the catalytic activity in correlation with the nature of the present counter ion and the size of the N-heterocyclic carbene (NHC) ligand were revealed. The presented methodology allows for preparation of a variety of polar and non-polar metathesis products under environmentally friendly conditions.
Gu?ajski, ?ukasz,Tracz, Andrzej,Urbaniak, Katarzyna,Czarnocki, Stefan J.,Bieniek, Micha?,Olszewski, Tomasz K.
supporting information
p. 160 - 166
(2019/01/30)

Acid-Assisted Direct Olefin Metathesis of Unprotected Carbohydrates in Water
The ability to use unprotected carbohydrates in olefin metathesis reactions in aqueous media is demonstrated. By using water-soluble, amine-functionalized Hoveyda–Grubbs catalysts under mildly acidic aqueous conditions, the self-metathesis of unprotected alkene-functionalized α-d-manno- and α-d-galactopyranosides could be achieved through minimization of nonproductive chelation and isomerization. Cross-metathesis with allyl alcohol could also be achieved with reasonable selectivity. The presence of small quantities (2.5 vol %) of acetic acid increased the formation of the self-metathesis product while significantly reducing the alkene isomerization process. The catalytic activity was furthermore retained in the presence of large amounts (0.01 mm) of protein, underlining the potential of this carbon–carbon bond-forming reaction under biological conditions. These results demonstrate the potential of directly using unprotected carbohydrate structures in olefin metathesis reactions under mild conditions compatible with biological systems, and thereby enabling their use in, for example, drug discovery and protein derivatization.
Timmer, Brian J. J.,Ramstr?m, Olof
supporting information
p. 14408 - 14413
(2019/11/11)

Ultra-Small Platinum Nanoparticles with High Catalytic Selectivity Synthesized by an Eco-friendly Method Supported on Natural Hydroxyapatite
Abstract: The biosynthesis of Pt-nanoparticles (Pt NPs) supported on bovine bone powder was conducted by an environmentally friendly method that consists on immersing bovine bone powder into a Pt4+ metal ion solution at room temperature, atmospheric pressure and subsequent reduction by Heterotheca inuloides. It is worth pointing out that a calcination process is not required for the synthesis of this catalyst by the method reported herein. The nanocomposite was characterized by transmission electron microscopy (TEM), which revealed uniformly dispersed platinum nanoparticles with quasi-spherical form and average particle size of 7.1?nm. The XPS studies exhibited the presence of 47.62% Pt° and 51.84% PtO. The catalyst activity was tested in the selective hydrogenation of 2-butyne-1,4-diol towards 2-butene-1,4-diol. The nanocomposite exhibits a reasonable catalytic performance with nearly 100% conversion of the alkyne and 96% selectivity towards 2-butene-1,4-diol. Graphic Abstract: [Figure not available: see fulltext.].
Gama-Lara,Natividad,Vilchis-Nestor,López-Casta?ares, Rafael,García-Orozco,Gonzalez-Pedroza, María G.,Morales-Luckie, Raúl A.
p. 3447 - 3453
(2019/08/12)

Polyhedral Cu2O to Cu pseudomorphic conversion for stereoselective alkyne semihydrogenation
Cu2O cubes, octahedra, and rhombic dodecahedra can be pseudomorphically converted into Cu crystals of corresponding shapes through reduction by ammonia borane in ethanol at 50 °C or below within 3 min, demonstrating the feasibility of making challenging polyhedral metal particles from metal oxide crystals. Hydrogen gas is also produced from ammonia borane in the process. The obtained Cu crystals have a slightly nanoporous interior. Addition of diphenylacetylene in the formation of Cu rhombic dodecahedra leads to complete stereoselective production of sterically hindered (Z)-stilbene. Semihydrogenation of other alkynes also gives pure (Z)-alkenes. Cu cubes and octahedra also showed considerable (Z)-stilbene selectivity along with minor formation of (E)-stilbene and bibenzyl as compared to CuCl2 and commercial Cu2O particles. Mechanistic studies reveal that the low binding affinity of alkenes on the rhombic dodecahedra surfaces leads to high product selectivity. These Cu crystals act as a green and low-cost catalyst for the synthesis of high-purity (Z)-alkenes.
Rej, Sourav,Madasu, Mahesh,Tan, Chih-Shan,Hsia, Chi-Fu,Huang, Michael H.
p. 2517 - 2524
(2018/03/08)

Accessing Frustrated Lewis Pair Chemistry through Robust Gold@N-Doped Carbon for Selective Hydrogenation of Alkynes
Pyrolysis of Au(OAc)3 in the presence of 1,10-phenanthroline over TiO2 furnishes a highly active and selective Au nanoparticle (NP) catalyst embedded in a nitrogen-doped carbon support, Au@N-doped carbon/TiO2 catalyst. Parameters such as pyrolysis temperature, type of support, and nitrogen ligands as well as Au/ligand molar ratios were systematically investigated. Highly selective hydrogenation of numerous structurally diverse alkynes proceeded in moderate to excellent yield under mild conditions. The high selectivity toward the industrially important alkene substrates, functional group tolerance, and the high recyclability makes the catalytic system unique. Both high activity and selectivity are correlated with a frustrated Lewis pairs interface formed by the combination of gold and nitrogen atoms of N-doped carbon that, according to density functional theory calculations, can serve as a basic site to promote the heterolytic activation of H2 under very mild conditions. This "fully heterogeneous" and recyclable gold catalyst makes the selective hydrogenation process environmentally and economically attractive.
Fiorio, Jhonatan Luiz,Gon?alves, Renato Vitalino,Teixeira-Neto, Erico,Ortu?o, Manuel A.,López, Núria,Rossi, Liane Marcia
p. 3516 - 3524
(2018/04/14)

Removable Water-Soluble Olefin Metathesis Catalyst via Host-Guest Interaction
A highly removable N-heterocyclic carbene ligand for a transition-metal catalyst in aqueous media via host-guest interactions has been developed. Water-soluble adamantyl tethered ethylene glycol in the ligand leads a hydrophobic inclusion into the cavity of β-cyclodextrin. Ruthenium (Ru) olefin metathesis catalyst with this ligand demonstrated excellent performance in various metathesis reactions in water as well as in CH2Cl2, and removal of residual Ru was performed via filtration utilizing a host-guest interaction and extraction.
Kim, Cheoljae,Ondrusek, Brian A.,Chung, Hoyong
supporting information
p. 736 - 739
(2018/02/09)

METHODS AND COMPOSITIONS FOR TERPENOID SYNTHESIS
In one aspect, the disclosure relates to methods for preparation of terpene and terpene-like molecules. In a further aspect, the disclosure relates to the products of the disclosed methods, i.e., terpene and terpene-like molecules prepared using the disclosed methods. Intermediates for the synthesis of a wide variety of terpenoids are γ-allyl Knoevenagel adducts or quasi γ-allyl Knoevenagel adducts are disclosed. In various aspects, methods of preparing terpenoids through these intermediates are disclosed. The methods can comprise α-alkylation of an allylic electrophile followed by ring-closure metathesis to a polycyclic terpenoid structure. In a further aspect, the disclosure pertains to terpenoid frameworks, and compounds prepared via disclosed oxidation and substitution reactions on the disclosed terpenoid frameworks. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.
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Paragraph 0090; 00143; 00146

(2018/04/13)

Palladium-Promoted Neutral 1,4-Brook Rearrangement/Intramolecular Allylic Cyclization Cascade Reaction: A Strategy for the Construction of Vinyl Cyclobutanols
A cascade reaction to build vinyl cyclobutanol rings through activation of vinyl epoxides by palladium, followed by 1,4-Brook rearrangement and intramolecular cyclization with a palladium complex of the resulting carbon anion, is described. Through this cascade reaction, several highly substituted cyclobutanol substrates were achieved in good yields with high stereoselectivities.
Zhang, Hao,Ma, Shiqiang,Yuan, Ziyun,Chen, Peng,Xie, Xingang,Wang, Xiaolei,She, Xuegong
supporting information
p. 3478 - 3481
(2017/07/15)

Unconventional Pd@Sulfonated Silica Monoliths Catalysts for Selective Partial Hydrogenation Reactions under Continuous Flow
Doubly functionalized, hierarchical-porosity silica monoliths were synthesized by postgrafting of sulfonic groups and in situ growth of Pd nanoparticles in that order. PdNP of 3.1 nm size located in the mesopores of the material showed to be evenly distributed within 4.6 % wt Pd monoliths. The system was explored in the continuous-flow, catalytic partial hydrogenation reaction of 3-halogeno-nitrobenzenes and 3-hexyn-1-ol in the liquid phase, showing remarkable conversion, selectivity, and resistance under very mild conditions.
Liguori, Francesca,Barbaro, Pierluigi,Said, Bilel,Galarneau, Anne,Santo, Vladimiro Dal,Passaglia, Elisa,Feis, Alessandro
p. 3245 - 3258
(2017/08/29)

BiCl3: A versatile catalyst for the tetrahydropyranylation and depyranylation of 1°,2°,3°, allylic, benzylic alcohols, and symmetric diols
Bismuth trichloride as mild reagent, has been found to be a worthful catalyst for tetrahydropyranylation of 1°,2°,3°, allylic, benzylic alcohols, and symmetric di-ols. At room temperature the reagent THP(3,4-dihydro-2H-pyran) was successfully employed as pyranylating agent in presence of BiCl3catalyst without the use of a solvent and the yields of the products were found to be 90-96%. Further, the depyranylation of alcohols was achieved in quantitative yield by simple addition of MeOH using the same catalyst. The developed method was showed good chemo-selectivity in symmetrical diols for mono THP protection.
Vijaya Durga,Balamurali Krishna,Baby Ramana,Santha Kumari,Vijay,Hari Babu
p. 1030 - 1034
(2017/05/26)

Method for preparing enol by semi-hydrogenating alkynol
The invention provides a method for preparing 1,4-butenediol by semi-hydrogenating 1,4-butynediol. The method comprises the following steps: pre-treating raw materials by utilizing an alkaline solution; and realizing the controllability of a hydrogenating step by adopting a gradient stirring method in the presence of a catalyst. According to the method, the liquid-solid ratio of 1,4-alkynediol to the catalyst is (80-200) to 1, and the operation temperature (30 DEG C-115 DEG C) and the pressure (0.3MP-1MPa) are relatively low; and the conversion ratio of the 1,4-butynediol reaches 99.9% and the selectivity and yield of the 1,4-butenediol reach 98.2% and 95.87%. According to the method provided by the invention, the charge density of the raw material is changed and the controllability of a hydrogenating process is realized in the presence of the catalyst through adjusting a stirring speed by gradient, and a relatively good semi-hydrogenating performance is represented; and the method has a good industrial application value.
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Paragraph 0097; 0098; 0099; 0100; 0101; 0102; 0103-0127

(2017/07/21)

Efficient Pd@MIL-101(Cr) hetero-catalysts for 2-butyne-1,4-diol hydrogenation exhibiting high selectivity
Pd@MIL-101(Cr) hetero-catalysts have been successfully prepared using the metal-organic chemical vapour deposition (MOCVD) approach, by choosing [Pd(η3-C3H5)(η5-C5H5)] as a volatile precursor, and the hydrothermally stable metal-organic framework, MIL-101(Cr) as a support. The prepared Pd@MIL-101(Cr) hetero-catalysts characterized with various analytical techniques, exhibited highly monodispersed immobilized Pd nanoparticles in the MIL-101(Cr) cavities, while retaining the pristine crystallinity and porosity. The intact hybrid Pd@MIL-101(Cr) has been demonstrated to be an efficient catalyst for 2-butyne-1,4-diol hydrogenation with excellent activity, stability and selectivity (2-butene-1,4-diol (>94%)).
Yin, Dongdong,Li, Chuang,Ren, Hangxing,Shekhah, Osama,Liu, Jinxuan,Liang, Changhai
p. 1626 - 1633
(2017/01/18)

Synthesis of highly selective nano-structured functionalized SBA-15 metformin palladium composite catalyst in partial hydrogenation of alkynes
In this research, a heterogeneous Nano-Structured functionalized SBA-15 metformin palladium composite catalyst is reported for the selective hydrogenation of alkynes. In the first place, A series of the heterogeneous mesoporous SBA-15 metformin palladium catalyst were prepared and afterwards the condition and the ratio of used materials were optimized to give rise a suitable high performance catalyst. The final nano-structured catalyst was characterized by X-ray powder diffraction, BET surface area, FT-IR spectrophotometer, Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) and served in partial hydrogenation of different alkynes, with high selectivity and high yield. The liquid phase hydrogenation was conducted under mild condition of room temperature and atmospheric pressure. The reactions were monitored every half an hour by gas chromatography and all of them were completed during 4-6 hours. The products were characterized by 1H-NMR, 13C-NMR, FT-IR, and Mass Spectrometry (MS) that strongly confirmed the (Z)-double bond configuration of produced alkenes. This prepared catalyst is competitive with the best palladium catalysts known for the selective liquid phase hydrogenation of alkynes and can be easily recovered and regenerated with keeping high activity and selectivity over multiple cycles with a simple regeneration procedure.
Kojoori, Reza Kia
p. 3144 - 3149
(2016/11/18)

Partial hydrogenation of alkynes on highly selective nano-structured mesoporous silica MCM-41 composite catalyst
In this research, we have developed a silica MCM-41/Metformin/Pd (II) nano composite catalyst for the selective hydrogenation of alkynes to the corresponding (Z)-alkenes under a mild condition of atmospheric pressure and room temperature. Firstly, functionalized Si-MCM-41 metformin catalyst with the optimum performance was prepared. Then, the synthesized catalyst was elucidated by X-ray powder diffraction, BET surface area, FT-IR spectrophotometer, Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) and applied in partial hydrogenation of different alkynes, with high selectivity and high yield. The products were characterized by 1H-NMR, 13C-NMR, FT-IR, and Mass Spectrometry (MS) that strongly approved the (Z)-double bond configuration of produced alkenes. This prepared catalyst is competitive with the best palladium catalysts known for the selective liquid phase hydrogenation of alkynes and can be easily recovered and regenerated with keeping high activity and selectivity over at least three cycles with a simple regeneration procedure.
Kojoori, Reza Kia
p. 1121 - 1128
(2017/01/25)

METHOD FOR PRODUCING ALLYL ALCOHOLS
PROBLEM TO BE SOLVED: To provide a method for producing allyl alcohols by direct addition of water to a raw material olefin which can achieve both high selectivity of compounds and high yield. SOLUTION: In a method for producing allyl alcohols by direct addition of water to a raw material olefin, the raw material olefin and water are brought into contact with a solid catalyst, where a catalytically active component containing at least one transition metal element selected from groups 8-10 of the periodic table is carried on an oxide carrier, in the presence of oxygen to convert the raw material olefin to allyl alcohols. SELECTED DRAWING: None COPYRIGHT: (C)2016,JPO&INPIT
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(2017/05/27)

Highly Efficient Catalytic Formation of (Z)-1,4-But-2-ene Diols Using Water as a Nucleophile
The first general catalytic and highly stereoselective formation of (Z)-1,4-but-2-ene diols is described from readily available and modular vinyl-substituted cyclic carbonate precursors using water as a nucleophilic reagent. These 1,4-diol scaffolds can be generally prepared in high yields and with ample scope in reaction partners using a simple synthetic method that does not require the presence of any additive or any special precaution unlike the stoichiometric approaches reported to date. Control experiments support the mechanistic view that hyperconjugation within the catalytic intermediate after decarboxylation plays an imperative role to control the stereoselective outcome of these reactions.
Guo, Wusheng,Martínez-Rodríguez, Luis,Martin, Eddy,Escudero-Adán, Eduardo C.,Kleij, Arjan W.
supporting information
p. 11037 - 11040
(2016/10/13)

Versatile PdTe/C catalyst for liquid-phase oxidations of 1,3-butadiene
A commercial Pd catalyst based on Sibunit carbon support was treated with H6TeO6 in a reducing media to obtain a Te coating on the surface of Pd particles. The PdTe/C catalyst prepared in this way showed the ability to control the radical chain oxidation of 1,3-butadiene by promoting the selective formation of 2-butene-1,4-diol, 4-hydroxybut-2-enal and furan in DMA (total selectivity of 61% and yield of 7%). At the same time, the catalyst induced oxidation of 1,3-butadiene by a non-radical heterolytic mechanism involving the formation of two groups of primary products: (1) crotonaldehyde and methyl vinyl ketone and (2) the products of oxygenation at the 1,4-positions. The compounds of the second group including 1,4-dimethoxy-2-butene and maleic acid dimethyl ester were formed on PdTe centers in MeOH. Increasing the Te concentration in the PdTe/C catalyst forced the conversion of 1,3-butadiene toward 1,4-oxygenation and simultaneously decreased the intensity of secondary oxidation, resulting in the selective formation of derivatives of the 1,4-oxygenation - 1,4-dimethoxy-2-butene and allenic alcohol methyl ether (total selectivity of 84% and yield of 48%).
Kuznetsova,Zudin,Kuznetsova,Zaikovskii,Kajitani,Utsunomiya,Takahashi
p. 30 - 38
(2016/01/12)

Photovoltaic-driven organic electrosynthesis and efforts toward more sustainable oxidation reactions
The combination of visible light, photovoltaics, and electrochemistry provides a convenient, inexpensive platform for conducting a wide variety of sustainable oxidation reactions. The approach presented in this article is compatible with both direct and indirect oxidation reactions, avoids the need for a stoichiometric oxidant, and leads to hydrogen gas as the only byproduct from the corresponding reduction reaction.
Nguyen, Bichlien H.,Perkins, Robert J.,Smith, Jake A.,Moeller, Kevin D.
p. 280 - 287
(2015/05/27)

Allyl sulphides in olefin metathesis: Catalyst considerations and traceless promotion of ring-closing metathesis
Allyl sulphides are reactive substrates in ruthenium-catalysed olefin metathesis reactions, provided each substrate is matched with a suitable catalyst. A profile of catalyst activity is described, along with the first demonstration of allyl sulphides as traceless promoters in relayed ring-closing metathesis reactions. This journal is
Edwards, Grant A.,Culp, Phillip A.,Chalker, Justin M.
supporting information
p. 515 - 518
(2015/02/19)

A simple and practical preparation of an efficient water soluble olefin metathesis catalyst
This study details homogeneous olefin metathesis in water catalysed by a di-ammonium functionalised Ru-alkylidene complex. A facile gram scale synthesis of an air stable catalyst precursor which can be readily converted to its water soluble derivative is described. The di-ammonium functionalised Ru-alkylidene complex facilitates a range of ring-closing metathesis (RCM) and cross-metathesis (CM) reactions in water.
Wang, Zhen J.,Jackson, W. Roy,Robinson, Andrea J.
supporting information
p. 3407 - 3414
(2015/06/25)

Divergent Approach to a Family of Tyrosine-Derived Ru-Alkylidene Olefin Metathesis Catalysts
A simple and generic approach to access a new family of Ru-alkylidene olefin metathesis catalysts with specialized properties is reported. This strategy utilizes a late stage, utilitarian Hoveyda-type ligand derived from tyrosine, which can be accessed via a multigram-scale synthesis. Further functionalization allows the catalyst properties to be tuned, giving access to modified second-generation Hoveyda-Grubbs-type catalysts. This divergent synthetic approach can be used to access solid-supported catalysts and catalysts that function under solvent-free and aqueous conditions.
Gleeson, Ellen C.,Wang, Zhen J.,Jackson, W. Roy,Robinson, Andrea J.
p. 7205 - 7211
(2015/07/28)

Structured catalyst
The present invention relates to novel structured catalysts based on sintered metal fibers (SMF) coated by a basic oxide layer with Pd-nanoparticles, to reactions of organic compounds with hydrogen in the presence of said catalyst and an organic base as well as to vitamins, carotinoids, perfume ingredients, and/or food or feed ingredients prepared by using this reaction.
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(2015/09/22)

Pd-Pb Alloy Nanocrystals with Tailored Composition for Semihydrogenation: Taking Advantage of Catalyst Poisoning
Metallic nanocrystals (NCs) with well-defined sizes and shapes represent a new family of model systems for establishing structure-function relationships in heterogeneous catalysis. Here in this study, we show that catalyst poisoning can be utilized as an efficient strategy for nanocrystals shape and composition control, as well as a way to tune the catalytic activity of catalysts. Lead species, a well-known poison for noble-metal catalysts, was investigated in the growth of Pd NCs. We discovered that Pb atoms can be incorporated into the lattice of Pd NCs and form Pd-Pb alloy NCs with tunable composition and crystal facets. As model catalysts, the alloy NCs with different compositions showed different selectivity in the semihydrogenation of phenylacetylene. Pd-Pb alloy NCs with better selectivity than that of the commercial Lindlar catalyst were discovered. This study exemplified that the poisoning effect in catalysis can be explored as efficient shape-directing reagents in NC growth, and more importantly, as a strategy to tailor the performance of catalysts with high selectivity.
Niu, Wenxin,Gao, Yongjun,Zhang, Weiqing,Yan, Ning,Lu, Xianmao
supporting information
p. 8271 - 8274
(2015/07/07)

Continuous flow olefin metathesis using a multijet oscillating disk reactor as the reaction platform
The multijet oscillating disk (MJOD) flow reactor is a relatively new technology for continuous flow synthesis. This technology is still under investigation as an all-round platform for flow synthesis. In this article, findings are disclosed from a project where a MJOD flow reactor rig (reactor volume of ≈50 mL) was investigated as the reaction platform for ring closing metathesis and cross (self) metathesis reaction, using reaction mixture volumes down to only ≈5 mL. The Hoveyda-Grubbs second-generation catalyst was used without an inert atmosphere. The results of the flow synthesis provided excellent selectivity and high yield. For comparison purposes, the syntheses conducted in the MJOD reactor were compared with similar literature experiments performed with other flow technologies and batch conditions.
Bjorsvik, Hans-Ren,Liguori, Lucia
p. 1509 - 1515
(2015/02/19)

Raney Ni-Si catalysts for selective hydrogenation of highly concentrated 2-butyne-1,4-diol to 2-butene-1,4-diol
Raney Ni-Si catalysts were synthesized by treating Raney Ni with silane in a fluidized bed reactor and tested in the selective hydrogenation of 2-butyne-1,4-diol (BYD) at high concentration. Structural characterizations including XRD patterns, TEM images, and X-ray photoelectron spectroscopy show that Raney Ni-Si catalysts are composed of a Ni core surrounded by nickel silicides. These species transform from Ni-rich silicide (Ni2Si) to Si-rich silicide (NiSi2) with increasing silicification temperature from 250 °C to 450 °C. The insertion of Si atoms into Raney Ni catalysts decreased the catalytic activity, but significantly improved the selectivity to 2-butene-1,4-diol (BED). The beneficial effect of Si on the selectivity hydrogenation of BYD may be caused by the presence of Si at Ni-defect sites, and the formation of the surface nickel silicide that suppress the further hydrogenation of BED. Compared with the traditional Lindlar-type catalysts, such Raney Ni-Si materials can be used extensively in organic synthesis for selective hydrogenation of alkynes, avoiding the associated hazards of toxic additives.
Chen, Xiao,Zhang, Mingming,Yang, Kaixuan,Williams, Christopher T.,Liang, Changhai
p. 1118 - 1126
(2014/07/21)

Sunlight, electrochemistry, and sustainable oxidation reactions
Inexpensive, readily available photovoltaic cells have been used to conduct indirect electrochemical oxidation reactions. The reactions retain the efficiency of the solar-electrochemical method while capitalizing on the unique opportunities for selectivity afforded by a chemical oxidant. The versatility of the electrochemical method allowed for the recycling of Os(viii)-, TEMPO-, Ce(iv)-, Pd(ii)-, Ru(viii)-, and Mn(v)-oxidants all with the same very simple reaction apparatus.
Nguyen, Bichlien H.,Redden, Alison,Moeller, Kevin D.
supporting information
p. 69 - 72
(2014/01/06)

Cyclopentanoids by uncatalyzed intramolecular carbonyl ene (ICE) reaction of α-keto esters
The uncatalyzed intramolecular carbonyl ene (ICE) reaction of substituted ε,ζ-unsaturated α-keto esters to terpenoid-related building blocks has been studied. We found a beneficial effect of a silyl substituent at the ene segment on the kinetics of the ICE reaction. A generalizable and scalable synthesis of ε,ζ-unsaturated α-keto esters from allylic alcohols was developed.
Tymann, David,Klueppel, Andre,Hiller, Wolf,Hiersemann, Martin
supporting information
p. 4062 - 4065
(2014/11/07)

Green semi-hydrogenation of alkynes by Pd@borate monolith catalysts under continuous flow
Palladium nanoparticles were immobilized onto an unconventional polymeric borate macroporous monolith and the resulting mesoreactor (i.d. 3 mm, length 25 mm) used in liquid-phase catalytic semi-hydrogenation reaction of substituted alkynes under continuous flow. The catalytic system showed excellent efficiency, both in terms of activity and selectivity, and long-term stability under mild reaction conditions (methanol, room temperature, 1.5 bar H2 max), with no need of additives. Particularly, the leaf alcohol cis-3-hexen-1-ol was for the first time obtained with selectivity comparable to that of the industrial batch process. The performance of the catalyst is discussed and compared with those of the analogous batch and industrial processes.
Liguori, Francesca,Barbaro, Pierluigi
p. 212 - 220
(2014/01/17)

Selective semihydrogenation of alkynes on shape-controlled palladium nanocrystals
A systematic study on the selective semihydrogenation of alkynes to alkenes on shape-controlled palladium (Pd) nanocrystals was performed. Pd nanocrystals with a cubic shape and thus exposed {100} facets were synthesized in an aqueous solution through the reduction of Na2PdCl4 with L-ascorbic acid in the presence of bromide ions. The Pd nanocubes were tested as catalysts for the semihydrogenation of various alkynes such as 5-decyne, 2-butyne-1,4-diol, and phenylacetylene. For all substrates, the Pd nanocubes exhibited higher alkene selectivity (>90 %) than a commercial Pd/C catalyst (75-90 %), which was attributed to a large adsorption energy of the carbon-carbon triple bond on the {100} facets of the Pd nanocubes. Our approach based on the shape control of Pd nanocrystals offers a simple and effective route to the development of a highly selective catalyst for alkyne semihydrogenation. Catalysis3: The semihydrogenation of various alkynes by Pd nanocubes was investigated. The nanocubes exhibited high alkene selectivity and complete cis-selectivity, thus surpassing the Lindlar catalyst. The shape control of Pd nanocrystals provides a simple and efficient way for generating highly selective catalysts for the semihydrogenation of alkynes.
Chung, Jooyoung,Kim, Chanhoi,Jeong, Hansaem,Yu, Taekyung,Binh, Do Huy,Jang, Jyongsik,Lee, Jaichan,Kim, B. Moon,Lim, Byungkwon
p. 919 - 925
(2013/08/25)

METATHESIS CATALYSTS CONTAINING ONIUM GROUPS
Disclosed herein is a general method for the preparation of complexes containing a quaternary onium group in an inert ligand. Some of these complexes may be represented by formula (1): Methods for the preparation of complexes of formula 1, the preparation
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(2013/09/12)

Catalytic properties of heteropoly compounds in 1,3-butadiene oxidation with hydrogen peroxide
The homogeneous oxidation of 1,3-butadiene (BD) in H2O 2-HPC-CH3CN (HPC = heteropoly compound) solutions has been investigated. The route of the reaction depends on the nature of the metal capable of coordinating with active oxygen in the HPC. The products of radical BD oxidation (acrolein, 3-butene-1,2-diol, 2-butene-1,4-diol, furan) form in the presence of H3+n PMo12 - n V n O40 (n = 1, 2) acids. 3,4-Epoxy-1-butene (EB) and acrolein + furan, which form in equal amounts in the presence of the (n-Bu4N)5PW 11O39Fe(OH) salt, result, respectively, from the electrophilic addition of hydrogen peroxide to BD and from radical BD oxidation on iron-oxygen complexes in the HPC composition. The reaction carried out in the presence of (n-Bu4N)3{PO4[WO(O 2)2]4}, (n-Bu4N)5Na 0.6H1.4PW11O39, or (EMIm) 5NaHPW11O39 yields EB with high selectivity on the reacted BD basis (up to 97%) and H2O2 (about 100%). The formation and conversion of the phosphotungstate peroxo complexes PW n O m α- (n = 2, 3, 4) that are active in BD epoxidation have been investigated by 31PNMR spectroscopy. The role of the tetrabutylammonium and ethylmethylimidazolium cations in the formation of these complexes has been demonstrated.
Kuznetsova,Kuznetsova,Maksimovskaya,Koshcheeva,Utkin
p. 420 - 430
(2013/12/04)

Liquid-phase catalytic hydrogenation of 2-butyne-1,4-diol to 1,4-butanediol at atmospheric pressure on suspended catalysts
The optimum parameters of hydrogenation of 2-butyne-1,4-diol to 1,4-butanediol on the suspended palladium and Ni-Raney catalysts at atmospheric pressure were found. In selected conditions a yield up to 90% of 1,4-butanediol was reached.
Pyatnitsyna,El'Chaninov
p. 394 - 397
(2013/06/27)

Catalytic deoxydehydration of diols to olefins by using a bulky cyclopentadiene-based trioxorhenium catalyst
A bulky cyclopentadienyl (Cp)-based trioxorhenium compound was developed for the catalytic deoxydehydration of vicinal diols to olefins. The 1,2,4-tri(tert-butyl)cyclopentadienyl trioxorhenium (2) catalyst was synthesised in a two-step synthesis procedure. Dirhenium decacarbonyl was converted into 1,2,4-tri(tert-butyl)cyclopentadienyl tricarbonyl rhenium, followed by a biphasic oxidation with H2O2. These two new three-legged compounds with a 'piano-stool' configuration were fully characterised, including their single crystal X-ray structures. Deoxydehydration reaction conditions were optimised by using 2 mol % loading of 2 for the conversion of 1,2-octanediol into 1-octene. Different phosphine-based and other, more conventional, reductants were tested in combination with 2. Under optimised conditions, a variety of vicinal diols (aromatic and aliphatic, internal and terminal) were converted into olefins in good to excellent yields, and with minimal olefin isomerisation. A high turnover number of 1400 per Re was achieved for the deoxydehydration of 1,2-octanediol. Furthermore, the biomass-derived polyols (glycerol and erythritol) were converted into their corresponding olefinic products by 2 as the catalyst. In the bulk of it: Bulky 1,2,4-tri(tert-butyl)cyclopentadienyl trioxorhenium was studied as a catalyst for the deoxydehydration of different vicinal diols. Under optimised conditions, a variety of vicinal diols were converted into olefins in good to excellent yields, and with minimal olefin isomerisation. Biomass-derived polyols were also converted into their corresponding olefinic products. Copyright
Raju, Suresh,Jastrzebski, Johann T. B. H.,Lutz, Martin,Klein Gebbink, Robertus J. M.
p. 1673 - 1680
(2013/10/21)