- FT Raman - A valuable tool for surveying kinetics in RCM of functionalized dienes
-
In this article the suitability of FT Raman spectroscopy for monitoring kinetics of ring-closing metathesis promoted by the Grubbs' 1st generation precatalyst was demonstrated for the first time. Reactions at room temperature and under low catalyst loadings were carried out on a series of representative diene substrates. The time evolution of the characteristic Raman stretching vibrations unequivocally described the reaction progress allowing for precise calculation of the substrate conversion and of the yield in the expected cyclic product, based on the corresponding peak heights. The responsive Raman technique demonstrated clean RCM pathways for diethyl diallylmalonate and diallyl ether whereas a minor olefinic side-product was detected in the case of diallyl phthalate. The study provides essential underpinnings for future utilization of Raman spectroscopy, concurrently with NMR or supplementing it, for the evaluation of RCM reactions.
- Ding, Fu,Yu, Baoyi,Monsaert, Stijn,Sun, Ya-Guang,Gao, Enjun,Dragutan, Ileana,Dragutan, Valerian,Verpoort, Francis
-
-
Read Online
- Supported Molybdenum Catalysts for the Deoxydehydration of 1,4-Anhydroerythritol into 2,5-Dihydrofuran
-
Efficient deoxygenation strategies are crucial for the valorization of renewable feedstocks. Deoxydehydration (DODH) enables the direct transformation of two adjacent hydroxyl groups into a double bond. Supported molybdenum-based catalysts were utilized for the first time in DODH. MoOx/TiO2 showed superior catalytic activity compared to common molybdenum salts. The catalyst efficiently converted 1,4-anhydroerythritol into 2,5-dihydrofuran in the presence of 3-octanol as reducing agent, showing high reproducibility and stability.
- Sandbrink, Lennart,Beckerle, Klaus,Meiners, Isabell,Liffmann, Rebecca,Rahimi, Khosrow,Okuda, Jun,Palkovits, Regina
-
-
Read Online
- Bidentate N,O-prolinate ruthenium benzylidene catalyst highly active in RCM of disubstituted dienes
-
The synthesis of a bidentate N,O-prolinate ruthenium benzylidene from commercially available starting materials and its activity in ring-closing metathesis of functionalized disubstituted dienes at 30°C is disclosed. The Royal Society of Chemistry.
- Samec, Joseph S. M.,Grubbs, Robert H.
-
-
Read Online
- HETEROCYCLIZATION OF 1-ACETOXY-4-HALO-SUBSTITUTED 2-BUTENES IN THE PRESENCE OF ALKALI
-
The reaction of 1-acetoxy-4-halo-substituted 2-butenes with potassium hydroxide was studied.It was established that trans-1,4-dihaloacetates form α-oxides of 1,3-dienes, whereas the corresponding cis isomers form 2,5-dihydrofuran derivatives.It was observed that the acetyl group in these compounds facilitates, as compared with halovinylhydrins, the formation of the corresponding heterocycles under the conditions described.
- Gevorkyan, A. A.,Kazaryan, P. I.,Avakyan, S. V.
-
-
Read Online
- Stepwise or Concerted Addition of 1,3-Butadiene to Oxygen Adsorbed on the Ag(110) Surface?
-
The interaction of 1,3-butadiene with atomically adsorbed oxygen on a Ag(110) surface is studied.Three different approaches of 1,3-butadiene to an oxygen atom that is adsorbed in the two-fold bridging site of the grooves on the Ag(110) surface are studied: a cheletropic 1,4-cycloaddition, an interaction with the terminal carbon, and an interaction with the internal carbon of the 1,3-butadiene.Extended Hueckel tight-binding calculations show that the interaction of one of the terminal carbons of 1,3-butadiene with the surface oxygen is favored.This intermediate shows a preference for a 1,4 ring closure reaction rather than a 1,2 ring closure reaction, leading to 2,5-dihydrofurane instead of vinyl epoxide.The interaction between the suggested intermediates and the Ag(110) surface as well as the bonding of different adsorbed products are analyzed and discussed in relation to the experimental results.
- Schioett, Birgit,Joergensen, Karl Anker
-
-
Read Online
- Microwave-Assisted Ring-Closing Metathesis Revisited. On the Question of the Nonthermal Microwave Effect
-
The ring-closing metathesis reactions (RCM) of six standard diene substrates leading to five-, six-, or seven-membered carbo- or heterocycles were investigated under controlled microwave irradiation. RCM protocols were performed with standard Grubbs type II and a cationic ruthenium allenylidene catalyst in neat and ionic liquid-doped methylene chloride under sealed vessel conditions. Very rapid conversions (15 s) were achieved utilizing 0.5 mol % Grubbs II catalyst under microwave conditions. Careful comparison studies indicate that the observed rate enhancements are not the result of a nonthermal microwave effect.
- Garbacia, Stefania,Desai, Bimbisar,Lavastre, Olivier,Kappe, C. Oliver
-
-
Read Online
- Bis(phenolato)molybdenum complexes as catalyst precursors for the deoxydehydration of biomass-derived polyols
-
Bio-based polyols can be converted to olefins and furan derivatives in one step by combined reduction and dehydration (deoxydehydration, DODH). A series of octahedral complexes of hexavalent molybdenum containing an (OSSO)-type bis(phenolate) ligand were prepared and structurally characterized. These complexes were screened as catalyst precursors for the deoxydehydration of anhydroerythritol using 3-octanol as reducing agent. Microwave heating allows a lower reaction temperature.
- Beckerle, Klaus,Sauer, Andreas,Spaniol, Thomas P.,Okuda, Jun
-
-
Read Online
- Ring-Closing Olefin Metathesis Catalyzed by Well-Defined Vanadium Alkylidene Complexes
-
Vanadium-based catalysts have shown activity and selectivity in ring-opening metathesis polymerization of strained cyclic olefins comparable to those of Ru, Mo, and W catalysts. However, the application of V alkylidenes in routine organic synthesis is limited. Here, we present the first example of ring-closing olefin metathesis catalyzed by well-defined V chloride alkylidene phosphine complexes. The developed catalysts exhibit tolerance to various functional groups, such as an ether, an ester, a tertiary amide, a tertiary amine, and a sulfonamide. The size and electron-donating properties of the imido group and the phosphine play a crucial role in the stability of active intermediates. Reactions with ethylene and olefins suggest that both β-hydride elimination of the metallacyclobutene and bimolecular decomposition are responsible for catalyst degradation.
- Belov, Dmitry S.,Tejeda, Gabriela,Tsay, Charlene,Bukhryakov, Konstantin V.
-
supporting information
p. 4578 - 4582
(2021/02/11)
-
- 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.
- -
-
Paragraph 0122; 0124-0125; 0136; 0138
(2020/07/02)
-
- 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
- -
-
Paragraph 0109-0111; 0129-0132; 0134-0135; 0150
(2020/10/31)
-
- N,N,O-Coordinated tricarbonylrhenium precatalysts for the aerobic deoxydehydration of diols and polyols
-
Rhenium complexes are well known catalysts for the deoxydehydration (DODH) of vicinal diols (glycols). In this work, we report on the DODH of diols and biomass-derived polyols using L4Re(CO)3as precatalyst (L4Re(CO)3= tricarbonylrhenium 2,4-di-tert-butyl-6-(((2-(dimethylamino)ethyl)(methyl)amino)methyl)phenolate). The DODH reaction was optimized using 2 mol% of L4Re(CO)3as precatalyst and 3-octanol as both reductant and solvent under aerobic conditions, generating the active high-valent rhenium speciesin situ. Both diol and biomass-based polyol substrates could be applied in this system to form the corresponding olefins with moderate to high yield. Typical features of this aerobic DODH system include a low tendency for the isomerization of aliphatic external olefin products to internal olefins, a high butadiene selectivity in the DODH of erythritol, the preferential formation of 2-vinylfuran from sugar substrates, and an overall low precatalyst loading. Several of these features indicate the formation of an active species that is different from the species formed in DODH by rhenium-trioxo catalysts. Overall, the bench-top stable and synthetically easily accessible, low-valent NNO-rhenium complex L4Re(CO)3represents an interesting alternative to high-valent rhenium catalysts in DODH chemistry.
- Klein Gebbink, Robertus J. M.,Li, Jing,Lutz, Martin
-
p. 3782 - 3788
(2020/06/22)
-
- Preparation method of 3-aminomethyl tetrahydrofuran
-
The invention relates to a preparation method of 3-aminomethyl tetrahydrofuran, and the preparation method comprises the following steps: cyclizing compound 1 cis-butenediol to obtain a compound 2, namely 2,5-dihydrofuran, then formylating the 2,5-dihydrofuran to obtain a compound 3, namely 3-formyl tetrahydrofuran, and finally performing reductive amination to obtain a compound 4, namely the 3-aminomethyl tetrahydrofuran. The preparation method has the advantages of simple production process, high utilization rate of materials, large production capacity, high selectivity, durability and highefficiency of catalysts in each step. The preparation method is simple in route and easy to scale up in industrialization.
- -
-
Paragraph 0025-0027
(2019/11/20)
-
- Preparation of Highly Active Monometallic Rhenium Catalysts for Selective Synthesis of 1,4-Butanediol from 1,4-Anhydroerythritol
-
1,4-Butanediol can be produced from 1,4-anhydroerythritol through the co-catalysis of monometallic mixed catalysts (ReOx/CeO2+ReOx/C) in the one-pot reduction with H2. The highest yield of 1,4-butanediol was over 80 %, which is similar to the value obtained over ReOx–Au/CeO2+ReOx/C catalysts. Mixed catalysts of CeO2+ReOx/C showed almost the same performance, giving 89 % yield of 1,4-butanediol. The reactivity trends of possible intermediates suggest that the reaction mechanism over ReOx/CeO2+ReOx/C is similar to that over ReOx–Au/CeO2+ReOx/C: deoxydehydration (DODH) of 1,4-anhydroerythritol to 2,5-dihydrofuran over ReOx species on the CeO2 support with the promotion of H2 activation by ReOx/C, isomerization of 2,5-dihydrofuran to 2,3-dihydrofuran catalyzed by ReOx on the C support, hydration of 2,3-dihydrofuran catalyzed by C, and hydrogenation to 1,4-butanediol catalyzed by ReOx/C. The reaction order of conversion of 1,4-anhydroerythritol with respect to H2 pressure is almost zero and this indicates that the rate-determining step is the formation of 2,5-dihydrofuran from the coordinated substrate with reduced Re in the DODH step. The activity of ReOx/CeO2+ReOx/C is higher than that of ReOx–Au/CeO2+ReOx/C, which is probably related to the reducibility of ReOx/C and the mobility of the Re species between the supports. High-valent Re species such as Re7+ on the CeO2 and C supports are mobile in the solvent; however, low-valent Re species, including metallic Re species, have much lower mobility. Metallic Re and cationic low-valent Re species with high reducibility and low mobility can be present on the carbon support as a trigger for H2 activation and promoter of the reduction of Re species on CeO2. The presence of noble metals such as Au can enhance the reducibility through the activation of H2 molecules on the noble metal and the formation of spilt-over hydrogen over noble metal/CeO2, as indicated by H2 temperature-programmed reduction. The higher reducibility of ReOx–Au/CeO2 lowers the DODH activity of ReOx–Au/CeO2+ReOx/C in comparison with ReOx/CeO2+ReOx/C by restricting the movement of Re species from C to CeO2.
- Wang, Tianmiao,Tamura, Masazumi,Nakagawa, Yoshinao,Tomishige, Keiichi
-
p. 3615 - 3626
(2019/07/15)
-
- METHOD OF CYCLIC COMPOUNDS PRODUCTION IN OLEFINE METATHESIS REACTION AND USE OF RUTHENIUM CATALYSTS IN PRODUCTION OF CYCLIC OLEFINS IN OLEFINE METATHESIS REACTION
-
The invention relates to a method for the preparation of cyclic compounds in the metathesis of olefins from acyclic dienes comprising terminal and/or non-terminal C=C double bonds; the invention also relates to the use of homogeneous ruthenium complexes and homogeneous ruthenium complexes deposited on a solid support as catalysts and/or pre-catalysts for the preparation of cyclic olefins in olefin metathesis reactions. Formula (I)
- -
-
Page/Page column 52; 53; 55; 56
(2018/11/22)
-
- A versatile biobased continuous flow strategy for the production of 3-butene-1,2-diol and vinyl ethylene carbonate from erythritol
-
A versatile, tunable and robust continuous flow procedure for the deoxydehydration (DODH) of biobased erythritol toward 3-butene-1,2-diol is described. The procedure relies on specific assets of multistep continuous flow processing. Detailed mechanistic and computational studies on erythritol show that either 3-butene-1,2-diol or butadiene are obtained in high selectivity and yield on demand, as a function of the DODH reagent/substrate ratio and of the process parameters. Short reaction times (1-15 min) at high temperature (225-275 °C) and moderate pressure are reported. 3-Butene-1,2-diol is then further converted downstream into its corresponding carbonate, i.e. 4-vinyl-1,3-dioxolan-2-one (vinyl ethylene carbonate), an important industrial building block. The carbonation step uses a supported organocatalyst, and could be directly concatenated to the first DODH step. This unprecedented procedure also relies on a unique combination of on- and off-line analytical protocols for reaction monitoring and product quantification, and offers a biobased strategy toward important industrial building blocks otherwise petrosourced.
- Tshibalonza, Nelly Ntumba,Gérardy, Romaric,Alsafra, Zouheir,Eppe, Gauthier,Monbaliu, Jean-Christophe M.
-
supporting information
p. 5147 - 5157
(2018/11/26)
-
- A Cptt-Based Trioxo-Rhenium Catalyst for the Deoxydehydration of Diols and Polyols
-
Trioxo-rhenium complexes are well known catalysts for the deoxydehydration (DODH) of vicinal diols (glycols). In this work, we report on the DODH of diols and biomass-derived polyols using CpttReO3 as a new catalyst (Cptt=1,3-di-tert-butylcyclopentadienyl). The DODH reaction was optimized using 2 mol % of CpttReO3 and 3-octanol as both reductant and solvent. The CpttReO3 catalyst exhibits an excellent activity for biomass-derived polyols. Specifically, glycerol is almost quantitatively converted to allyl alcohol and mucic acid gives 75 % of muconates at 91 % conversion. In addition, the loading of CpttReO3 can be reduced to 0.1 mol % to achieve a turn-over number as high as 900 per Re when using glycerol as substrate. Examination of DODH reaction profiles by NMR spectroscopy indicates that catalysis is related to Cp-ligand release, which raises questions on the nature of the actual catalyst.
- Li, Jing,Lutz, Martin,Otte, Matthias,Klein Gebbink, Robertus J. M.
-
p. 4755 - 4760
(2018/10/02)
-
- Production technology of 3-aminomethyl tetrahydrofuran
-
The invention discloses a production technology of 3-aminomethyl tetrahydrofuran, and belongs to the field of pesticide intermediate synthesis technology. The technology takes 2-butene-1,4-diol as a starting material, and the starting material is synthesized 3-aminomethyl tetrahydrofuran through dehydration cyclization, hydroformylation and reductive amination reaction. The production technology is mild in reaction conditions, and is low in cost, less in three wastes, and suitable for industrial production.
- -
-
Paragraph 0046; 0051; 0054; 0056
(2018/09/08)
-
- Production technology for 3-hydroxymethyltetrahydrofuran
-
The invention discloses a production technology for 3-hydroxymethyltetrahydrofuran, and belongs to the field of pesticide intermediate synthetic processes. The production technology is capable of using 2-butene-1,4-diol as a starting raw material, and synthesizing the 3-hydroxymethyltetrahydrofuran through a three-step reaction of dehydration cyclization, hydroformylation and reduction. The production technology is moderate in reaction conditions, low in cost, less in three wastes, and suitable for the industrial production.
- -
-
Paragraph 0031; 0036; 0039; 0041
(2018/10/19)
-
- One-pot catalytic selective synthesis of 1,4-butanediol from 1,4-anhydroerythritol and hydrogen
-
A physical mixture of ReOx-Au/CeO2 and carbon-supported rhenium catalysts effectively converted 1,4-anhydroerythritol to 1,4-butanediol with H2 as a reductant. The combination of these two catalysts in a one-pot reaction dramatically increased the selectivity of 1,4-butanediol as well as the conversion of 1,4-anhydroerythritol. The yield of 1,4-butanediol reached ～90%, which is the highest yield from erythritol and 1,4-anhydroerythritol so far, furthermore, at a relatively low reaction temperature of 413 K. This reaction involves the ReOx-Au/CeO2-catalyzed deoxydehydration of 1,4-anhydroerythritol to 2,5-dihydrofuran and ReOx/C-catalyzed successive isomerization, hydration and reduction reactions of 2,5-dihydrofuran.
- Wang, Tianmiao,Liu, Sibao,Tamura, Masazumi,Nakagawa, Yoshinao,Hiyoshi, Norihito,Tomishige, Keiichi
-
supporting information
p. 2547 - 2557
(2018/06/18)
-
- Hoveyda-Type Quinone-Containing Complexes – Catalysts to Prevent Migration of the Double Bond under Metathesis Conditions
-
Three new quinone-containing Hoveyda-type complexes have been synthesised and fully characterised. Their ability to suppress undesired double-bond migration along the carbon chain during metathesis reactions was examined. It was proved that these catalysts decrease the amounts of undesired side-products with a shifted double bond in the reaction mixture.
- Kajetanowicz, Anna,Milewski, Mariusz,Rogińska, Joanna,Gajda, Roman,Wo?niak, Krzysztof
-
p. 626 - 638
(2017/02/05)
-
- N-Heterocyclic Carbene Complexes Of Metal Imido Alkylidenes And Metal OXO Alkylidenes, And The Use Of Same
-
The invention relates to an N-heterocyclic carbene complex of general formulas I to IV (I) (II) (III) (IV), according to which A1 stands for NR2 or PR2, A2 stands for CR2 R2′, NR2, PR2, 0 or S, A3 stands for N or P, and C stands for a carbene carbon atom, ring B is an unsubstituted or a mono or poly-substituted 5 to 7-membered ring, substituents R2 and R2′ stand, inter alia, for a linear or branched C1-Cw-alkyl group and, if N and N each stand for NR2 or PR2, are the same or different, M in formulas I, II, III or IV stands for Cr, Mo or W, X 1 or X2 in formulas I to IV are the same or different and represent, inter alia, C1-C1s carboxylates and C1-C1s-alkoxides, Y is inter alia oxygen or sulphur, Z is inter alia a linear or branched C1-Cw-alkylenoxy group, and R 1 and R1′ in formulas I to IV are, inter alia, an aliphatic or aromatic group. These compounds are particularly suitable for use as catalysts for olefin metathesis reactions and have the advantage, compared to known Schrock carbene complexes, of displaying clearly increased tolerance to functional groups such as, in particular, aldehydes, secondary amines, nitriles, carboxylic acids and alcohols.
- -
-
Paragraph 0181
(2017/03/21)
-
- Deoxydehydration of vicinal diols and polyols catalyzed by pyridinium perrhenate salts
-
Simple ammonium and pyridinium perrhenate salts were evaluated as catalysts for the deoxydehydration (DODH) of diols into alkenes. Pyridinium perrhenates were found to be effective catalysts at much lower temperatures than those in previous reports, outperforming primary, secondary, and tertiary ammonium salts, while quaternary ammonium salts are effectively inactive. The mechanism of reaction was studied computationally using DFT calculations which indicate that proton shuttling between the ion pair is intrinsic to the mechanism and that the reduction of rhenium by the phosphine occurs before the diol condensation.
- Morris, Danny S.,Van Rees, Karlotta,Curcio, Massimiliano,Cokoja, Mirza,Kühn, Fritz E.,Duarte, Fernanda,Love, Jason B.
-
p. 5644 - 5649
(2017/12/07)
-
- Synthetic method of 3-aminomethyl tetrahydrofuran
-
The invention discloses a synthetic method of 3-aminomethyl tetrahydrofuran. The synthetic method comprises the following steps: (1) carrying out cyclization reaction on 1,4-butylene glycol under the action of a fixed acid catalyst, so as to generate 2,5-dihydrofuran; (2) carrying out hydroformylation reaction on 2,5-dihydrofuran under the action of a homogeneous catalyst HRhCO[P(PhX)3]3, so as to obtain 3-formaldehyde tetrahydrofuran; (3) reacting by virtue of 3-formaldehyde tetrahydrofuran and hydroxylamine compounds, so as to obtain 3-formoxime tetrahydrofuran; and (4) carrying out hydrogenation on 3-formoxime tetrahydrofuran, so as to obtain 3-aminomethyl tetrahydrofuran. The synthetic method disclosed by the invention is environmentally friendly and has the beneficial effects that the process is simple, the steps are short, the total yield is very high, the cost is low, the yield of products in each step is higher than 90%, and the total yield of the finally prepared 3-aminomethyl tetrahydrofuran is higher than 80%.
- -
-
Paragraph 0033; 0045; 0052; 0059; 0066; 0073
(2017/07/20)
-
- Molybdenum Imido Alkylidene N-Heterocyclic Carbene Complexes: Structure–Productivity Correlations and Mechanistic Insights
-
The syntheses and single-crystal X-ray structures of a series of Mo–imido alkylidene N-heterocyclic carbene (NHC) complexes (1–15) and of the first complexes containing bidentate NHC-phenolate ligands (16–18) are reported. Mo(N-2,6-Me2-C6H3)((1-R-phenethyl)-3-mesitylimidazolidin-2-ylidene)(CHR)(OTf)2 (R=CMe2Ph, 1) is the first enantiomerically pure Mo–imido alkylidene NHC catalyst. With [Mo(N-2,6-Me2-C6H3)(IMes)(CHR)(CH3CN)(OTf)(CH3CN)+ B(ArF)4?] (7), turnover numbers up to 545 000 were achieved in the homometathesis (HM) of 1-octene and 1-nonene (≤95 percent E). With 7 and 1-nonene, a turnover frequency (TOF4 min) of 8860 min?1 was determined. Productivity and E/Z-selectivity were correlated with catalyst structure. For 1, Mo(N-3,5-Me2-C6H3)(IMesH2)(CHR)(OTf)2 (9) and Mo(N-3,5-Me2-C6H3)(IMes)(CHR)(OTf)2 (10), productivity was correlated with the coalescence temperature of the two triflates, determined by variable-temperature 19F NMR spectroscopy. The square-planar conformer is postulated to be the most relevant for the catalyst activation.
- Buchmeiser, Michael R.,Sen, Suman,Lienert, Christina,Widmann, Laura,Schowner, Roman,Herz, Katharina,Hauser, Philipp,Frey, Wolfgang,Wang, Dongren
-
p. 2710 - 2723
(2016/08/30)
-
- Methods for providing bond activation catalysts and related catalysts, systems, and methods
-
Described herein are catalysts for activation of an R—H bond in a R—H substrate and related catalytic matrices, compositions, methods and systems.
- -
-
-
- Encapsulation of Hoveyda-Grubbs2nd Catalyst within Yolk-Shell Structured Silica for Olefin Metathesis
-
Through postreducing the pore size of a mesoporous shell, Hoveyda-Grubbs2nd catalyst was successfully encapsulated within yolk-shell structured silica, leading to a heterogeneous catalyst for olefin metathesis. Such a catalyst exhibits much higher activity than the reported encapsulated catalysts in olefin ring-closing metathesis and cross metathesis. This excellent activity can be attributed to the combination of a hollow structure in the interior and permeable mesopores in the shells. This catalyst shows good recyclability, highlighted by eight cycles of reaction. This work not only supplies an excellent heterogeneous olefin metathesis catalyst but also demonstrates that yolk-shell structured silica materials can be used as an innovative scaffold to encapsulate homogeneous catalysts.
- Li, Qibiao,Zhou, Ting,Yang, Hengquan
-
p. 2225 - 2231
(2015/04/14)
-
- Synthesis of common-sized heterocyclic compounds by intramolecular cyclization over halide cluster catalysts
-
Five- to seven-membered common-sized heterocyclic compounds containing an oxygen, sulfur, or nitrogen were synthesized by the intramolecular condensation of α,ω-hydroxy, mercapto, or amino alkanes, respectively, over halide cluster complexes as a thermally stable molecular solid weak acid catalyst in the gas phase at temperatures ≥150 °C. From ω- mercapto and ω-amino alcohols, cyclic sulfides and amines were obtained, respectively. These unimolecular reactions are thermodynamically and kinetically favored.
- Nagashima, Sayoko,Sasaki, Tomoaki,Kamiguchi, Satoshi,Chihara, Teiji
-
supporting information
p. 764 - 766
(2015/06/22)
-
- Methods for providing bond activation catalysts and related catalysts, systems, and methods
-
Described herein are catalysts for activation of an R—H bond in a R—H substrate and related catalytic matrices, compositions, methods and systems.
- -
-
Page/Page column
(2014/09/03)
-
- Encapsulation of an olefin metathesis catalyst in the nanocages of SBA-1: Facile preparation, high encapsulation efficiency, and high activity
-
By postreducing the window size through silylation, 2nd generation Hoveyda-Grubbs catalyst was encapsulated in the nanocages of a mesoporous material SBA-1. The encapsulation efficiency of SBA-1 was up to 70%, much higher than that of other mesoporous materials such as SBA-16, FDU-12, and MCM-41 (0-43%). The successful encapsulation was confirmed by N2 sorption analysis and FTIR and diffusion reflectance UV/Vis spectroscopy. Such a SBA-1-encapsulated catalyst showed good activity in both olefin ring-closing metathesis and cross metathesis. A wide range of olefins could be transformed to the desired products with conversions of 27-100%. The encapsulated catalyst showed more sensitive temperature effects than the homogeneous counterpart, reflecting the unique properties of the encapsulated catalyst. At reaction temperatures of 40-60°C, the activity of the encapsulated catalyst was sufficiently comparable to that of the homogeneous catalyst for the cross metathesis of styrene-type substrates, probably because of the confinement effects of the nanocages. The solid catalyst could be recycled seven times. This study not only supplies a new solid catalyst for olefin metathesis but also demonstrates our improvement in immobilizing metal complex catalyst toward a green and effective level.
- Yang, Hengquan,Ma, Zhancheng,Zhou, Ting,Zhang, Wenjuan,Chao, Jianbin,Qin, Yong
-
p. 2278 - 2287
(2013/08/23)
-
- Expanding the scope of biomass-derived chemicals through tandem reactions based on oxorhenium-catalyzed deoxydehydration
-
New modes of DODH: Oxorhenium compounds act as deoxydehydration(DODH)/acid dual-purpose catalysts to transform biomass-derived diol substrates into a variety of commodity chemical precursors. The power of this approach is highlighted by a tandem [1,3]-OH shift/DODH of 2-ene-1,4-diols and 2,4-diene-1,6-diols, and by a DODH/esterification sequence of sugar acids to unsaturated esters for the production of polymers and plasticizers. Copyright
- Shiramizu, Mika,Toste, F. Dean
-
supporting information
p. 12905 - 12909
(2014/01/06)
-
- 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)
-
- Mechanism of MTO-catalyzed deoxydehydration of diols to alkenes using sacrificial alcohols
-
Catalytic deoxydehydration (DODH) of vicinal diols is carried out employing methyltrioxorhenium (MTO) as the catalyst and a sacrificial alcohol as the reducing agent. The reaction kinetics feature an induction period when MTO is added last and show zero-order in [diol] and half-order dependence on [catalyst]. The rate-determining step involves reaction with alcohol, as evidenced by a KIE of 1.4 and a large negative entropy of activation (ΔS? = -154 ± 33 J mol-1 K -1). The active form of the catalyst is methyldioxorhenium(V) (MDO), which is formed by reduction of MTO by alcohol or via a novel C-C bond cleavage of an MTO-diolate complex. The majority of the MDO-diolate complex is present in dinuclear form, giving rise to the [Re]1/2 dependence. The MDO-diolate complex undergoes further reduction by alcohol in the rate-determining step to give rise to a putative rhenium(III) diolate. The latter is the active species in DODH extruding stereoselectively trans-stilbene from (R,R)-(+)-hydrobenzoin to regenerate MDO and complete the catalytic cycle.
- Liu, Shuo,Senocak, Aysegul,Smeltz, Jessica L.,Yang, Linan,Wegenhart, Benjamin,Yi, Jing,Kenttaemaa, Hilkka I.,Ison, Elon A.,Abu-Omar, Mahdi M.
-
supporting information
p. 3210 - 3219
(2013/07/19)
-
- Synthesis of five-membered cyclic ethers by reaction of 1,4-diols with dimethyl carbonate
-
The reaction of 1,4-diols with dimethyl carbonate in the presence of a base led to selective and high-yielding syntheses of related five-membered cyclic ethers. This synthetic pathway has the potential for a wide range of applications. Distinctive cyclic ethers and industrially relevant compounds were synthesized in quantitative yield. The reaction mechanism for the cyclization was investigated. Notably, the chirality of the starting material was maintained. DFT calculations indicated that the formation of five-membered cyclic ethers was energetically the most favorable pathway. Typically, the selectivity exhibited by these systems could be rationalized on the basis of hard-soft acid-base theory. Such principles were applicable as far as computed energy barriers were concerned, but in practice cyclization reactions were shown to be entropically driven. Copyright
- Aricó, Fabio,Tundo, Pietro,Maranzana, Andrea,Tonachini, Glauco
-
experimental part
p. 1578 - 1586
(2012/10/07)
-
- Deoxygenation of biomass-derived feedstocks: Oxorhenium-catalyzed deoxydehydration of sugars and sugar alcohols
-
Turn sugar into oil: The deoxygenation reaction of sugar moieties is important for the conversion of biomass into chemicals and fuels. The methyltrioxorhenium-catalyzed deoxydehydration reaction was successfully applied to this purpose using another alcohol as solvent/reductant. The reaction was highly stereospecific, affording linear polyene products from C 4-C6 sugar alcohols and aromatic compounds from C 4-C6 sugars. Copyright
- Shiramizu, Mika,Toste, F. Dean
-
scheme or table
p. 8082 - 8086
(2012/09/08)
-
- Ruthenium-catalyzed ring-closing metathesis accelerated by long-range steric effect
-
Ruthenium-based metathesis catalysts with a N-heterocyclic carbene ligand bearing 2,3,4,5-tetraphenylphenyl moieties (1-TPPh and 1-TPPh*) are developed. The highly active catalyst system has been realized in THF by the combination of 1-TPPh* and CuCl as a phosphine scavenger. The Royal Society of Chemistry 2011.
- Fujihara, Tetsuaki,Tomike, Yoshikazu,Ohtake, Toshiyuki,Terao, Jun,Tsuji, Yasushi
-
supporting information; experimental part
p. 9699 - 9701
(2011/10/08)
-
- METHOD FOR PRODUCING VINYL ETHER COMPOUND
-
The invention provides a method for producing a vinyl ether compound, characterized in that the method includes isomerizing an allyl ether compound represented by formula (I) or (II): (wherein R1 represents a C1 to C6 alkyl group; each of R2, R3, and R4 independently represents a hydrogen atom, a C1 to C6 alkyl group, or a C3 to C6 alkenyl group; and n is 1 or 2) in the presence of hydrogen, a monodentate tris(ortho-substituted aryl) phosphite, and a rhodium compound. The vinyl ether compound is useful as a raw material, an intermediate, etc. for producing pharmaceuticals, agrochemicals, polymers, etc.
- -
-
Page/Page column 8-9
(2011/02/19)
-
- Intramolecular condensation of 1,2-C6H4(CH 2RH)2 (R = O, S, and NH) to yield heterocyclic compounds over halide-cluster catalysts
-
1,2-Benzenedimethanol was reacted under a helium stream in the presence of [(Nb6Cl12)Cl2(H2O) 4]·4H2O supported on silica gel. When the temperature was raised above 200 °C, catalytic activity of the cluster for cyclization appeared, yielding 1,3-dihydroisobenzofuran in 91% selectivity at 350 °C. The corresponding halide clusters of tantalum and tungsten also catalyzed the reaction. cis-1,2-Cyclohexanedimethanol and 1,4-butanediol exclusively produced the corresponding furans. 1,2-Benzenedimethanamine and 1,2-benzenedimethanethiol selectively afforded isoindoline and 1,3-dihydrobenzo[c]thiophene, respectively.
- Nagashima, Sayoko,Kamiguchi, Satoshi,Kudo, Kentaro,Sasaki, Tomoaki,Chihara, Teiji
-
scheme or table
p. 78 - 80
(2011/05/07)
-
- Sulfite-driven, oxorhenium-catalyzed deoxydehydration of glycols
-
Methyltrioxorhenium and perrhennate salts catalyze the deoxydehydration (DODH) of glycols by sulfite, producing olefins regiospecifically. The scope and efficiency of these reactions with respect to the polyol substrate, reducing agent, catalyst, solvents, and various additives are investigated. In general, MeReO3 is a more active catalyst for sulfite-driven DODH, but the Z+ReO4- derivatives (Z = Na, Bu4N) are more selective. Epoxides are also deoxygenated by Na2SO 3/MeReO3, but not by Bu4NReO4. The perrhenate catalysts also promote glycol DODH with other reductants, e.g., PR3, secondary alcohols, and ArSMe. The DODH reactions of 1,2-cyclohexanediol and (+)-diethyl tartrate occur with high syn-stereoselectivity. The polyol meso-erythritol is largely converted to 1,3-butadiene with minor amounts of 2-butene-1,4-diol and 2,5-dihydrofuran, indicating faster terminal glycol DODH. Stoichiometric reaction studies demonstrate the viability of a catalytic pathway involving (a) glycol condensation with MeReO3 to form MeReVIIO 2(glycolate); (b) O-transfer reduction of the ReVII- glycolate by sulfite or PR3 to produce [MeRevO(glycolate)] 2; and (c) thermal fragmentation of the reduced Re-glycolates to produce olefin (and regeneration of MeReO3).
- Ahmad, Irshad,Chapman, Garry,Nicholas, Kenneth M.
-
experimental part
p. 2810 - 2818
(2011/07/31)
-
- Hoveyda-Grubbs catalyst confined in the nanocages of SBA-1: Enhanced recyclability for olefin metathesis
-
Via a simple adsorption, the second generation Hoveyda-Grubbs catalyst was successfully immobilized on a mesoporous material SBA-1, leading to a highly recyclable solid catalyst for olefin metathesis.
- Yang, Hengquan,Ma, Zhancheng,Wang, Yuekui,Wang, Yunwei,Fang, Li
-
supporting information; experimental part
p. 8659 - 8661
(2011/01/03)
-
- Synthesis and reactivity of molybdenum imido alkylidene bis-pyrazolide complexes
-
Reaction of Li(3,5-R2-pyrazolide) (R = tBu or Ph, dXpz) with Mo(NAr)(CHCMe2Ph)(OTf)2(DME) yields Mo(NAr)(CHCMe 2Ph)(dXpz)2 in good yield. These complexes react with alcohols or the surface silanols of silica, to yield bis-alkoxy and surface mono-siloxy alkene metathesis catalysts, respectively.
- Gajan, David,Rendon, Nuria,Wampler, Keith M.,Jean-Marie Basset,Coperet, Christophe,Lesage, Anne,Emsley, Lyndon,Schrock, Richard R.
-
experimental part
p. 8547 - 8551
(2011/01/07)
-
- Conversion of cis-2-butene-1,4-diol to hydrofurans on Pd/SiO2 and Pt/SiO2 catalysts under mild conditions: A FT-IR study
-
The gas-phase interaction of cis-2-butene-1,4-diol (C-2-OL) with silica supported Pd and Pt nanoparticles has been studied using infrared spectroscopy at room temperature. Samples were prepared according to standard recipes and characterized through TEM and the IR spectroscopy of adsorbed carbon monoxide at room temperature. Whereas the reaction with hydrogen of C-2-OL in ethanol solutions yields hydrogenated products through a complex network, and no reaction takes place in the absence of hydrogen, in the present case C-2-OL is converted first to 2,5-dihydrofuran (2,5-DHF) and water. This step occurs on the silica support at room temperature, probably through the intermediacy of the surface species -Si-O-CH2-CHCH-CH2-OH. The presence of Pd nanoparticles allows, at ca. 100 °C, the subsequent isomerization of 2,5-DHF to 2,3-dihydrofuran (2,3-DHF). The same reaction requires a higher temperature (ca. 150 °C) with the Pt catalyst. At higher temperatures, the expected dehydrogenation of both 2,5- and 2,3-DHFs to furan takes place. On the support alone at 350 °C 2,5-DHF is converted to furan, and 2,3-DHF to carbonyl-containing species (as suggested in the literature), through thermal reactions.
- Mauriello, Francesco,Garrone, Edoardo,Musolino, Maria Grazia,Pietropaolo, Rosario,Onida, Barbara
-
scheme or table
p. 27 - 34
(2010/12/18)
-
- Rhenium-catalyzed didehydroxylation of vicinal diols to alkenes using a simple alcohol as a reducing agent
-
A new method for the catalytic didehydroxylation of vicinal diols is described. Employing a readily available low-valent rhenium carbonyl complex and a simple alcohol as a reducing agent, both terminal and internal vicinal diols are deoxygenated to olefins in good yield. The optional addition of acid (TsOH, H2SO4) provides access to lower reaction temperatures. This new system enables the transformation of a four-carbon sugar polyol into an oxygen-reduced compound, providing promising evidence for its practical application to produce unsaturated compounds from biomass-derived materials.
- Arceo, Elena,Ellman, Jonathan A.,Bergman, Robert G.
-
supporting information; experimental part
p. 11408 - 11409
(2010/10/03)
-
- Weil-defined silica-supported olefin metathesis catalysts
-
Two triethoxysilyl-functionalized N-heterocyclic carbene ligands have been synthesized and used to prepare the corresponding second-generation ruthenium olefin metathesis catalysts. These complexes were then grafted onto silica gel, and the resulting materials were efficient heterogeneous catalysts for a number of metathesis reactions. The solid-supported catalysts were shown to be recyclable over a number of reaction cycles, and no detectable levels of ruthenium were observed in reaction filtrates (ruthenium concentration of filtrate 5 ppb).
- Allen, Daryl P.,Wingerden, Matthew M. Van,Grubbs, Robert H.
-
supporting information; experimental part
p. 1261 - 1264
(2009/09/25)
-
- Batchwise and continuous organophilic nanofiltration of Grubbs-type olefin metathesis catalysts
-
A mass-tagged N-mesityl imidazolinium salt with four additional -CH 2NCy2 substituents was synthesized, leading to a molecular mass of nearly 1100 g mol-1 in the corresponding carbene ligand. This mass-tagged ligand was used to generate the respective Grubbs II and Grubbs-Hoveyda type complexes. The catalytic activity of the latter complex was tested in several olefin metathesis reactions and found to be slightly superior to that of the related N-mesityl based complex. In batchwise solvent resistant nanofiltration experiments the ruthenium complex dissolved in toluene and following a metathesis reactions was efficiently retained (>99.8%) by a single nanofiltration; the permeate contained less than 4 ppm of Ru. Equally efficient catalyst retention was observed in a membrane reactor utilized for the continuous synthesis of a RCM product.
- Schoeps, Dirk,Buhr, Kristian,Dijkstra, Marga,Ebert, Katrin,Plenio, Herbert
-
experimental part
p. 2960 - 2965
(2009/12/08)
-
- METHOD FOR CONTINUOUSLY PRODUCING 2,5-DIHYDROFURAN
-
The method of the invention for continuously producing 2,5-dihydrofuran includes subjecting cis-2-butene-1,4-diol to liquid-phase dehydration-cyclization reaction in the presence of alumina, characterized in that the sum of the concentration of carbonyl compounds present in the reaction system and the concentration of acetal compounds present in the reaction system is controlled to fall within a range of 0.1 to 2 mol/L, provided that the concentration of the acetal compounds is calculated in terms of acetal groups, the concentrations being determined on the basis of the total amount of the reaction mixture. According to the method, 2,5-dihydrofuran, which is useful as a raw material or intermediate for producing pharmaceuticals, agrochemicals, raw materials of polymers, etc., can be continuously produced. The method can prevent inactivation of γ-alumina and is advantageous for long-term production on an industrial scale.
- -
-
Page/Page column 10
(2009/12/27)
-
- An efficient didehydroxylation method for the biomass-derived polyols glycerol and erythritol. Mechanistic studies of a formic acid-mediated deoxygenation
-
An efficient 1,2-deoxygenation method, involving an unexpected mechanism, was found for simple diols and for biomass-derived polyols (glycerol and erythritol) that results in the conversion of the 1,2-dihydroxy group to a carbon-carbon double bond.
- Arceo, Elena,Marsden, Peter,Bergman, Robert G.,Ellman, Jonathan A.
-
supporting information; experimental part
p. 3357 - 3359
(2009/12/26)
-
- CYCLIC ETHERS
-
A process of preparing cyclic ethers is described. The process involves the reaction of at least one organic compound such as a dioi or a polyol which it has at least one pair of hydroxyl groups separated by 4 or 5 carbon atoms, and which is capable of being converted into an ether linkage, with an organic carbonate in the presence of a base. The base is an alkoxy, a carbonate or a hydroxide base or is a mixture of such bases. At least one of the hydroxyl groups of the organic compound is not a tertiary hydroxyl group.
- -
-
Page/Page column 10; 14
(2009/03/07)
-
- Olefin ring closing metathesis and hydrosilylation reaction in aqueous medium by grubbs second generation ruthenium catalyst
-
(Chemical Equation Presented) The Grubbs second generation ruthenium catalyst was shown to catalyze various olefin ring closing metathesis and hydrosilylation reactions in aqueous medium. Reactions proceeded in pure water without any additives or cosolvents, in a short period of time. We found that inhomogeneity of the reaction mixture does not prevent high conversion (70-95%) of the products in both reactions.
- Polshettiwar, Vivek,Varma, Rajender S.
-
supporting information; experimental part
p. 7417 - 7419
(2009/05/07)
-
- Immobilized ruthenium complexes bearing N,O-bidentate ligands
-
Immobilization of a family of arene and benzylidene N,O-bidentate ruthenium complexes by covalently anchoring the homogeneous complexes on MCM-41 is described. Successful applications of these immobilized catalytic systems in enol-ester synthesis, Kharasch addition, ring-closing metathesis (RCM), ring-opening metathesis polymerization (ROMP) and atom transfer radical polymerization (ATRP) are illustrated. Important advantages of these heterogeneous catalyst systems in comparison with their homogeneous counterparts are also highlighted.
- Drǎgu?an, Valerian,Verpoort, Francis
-
p. 905 - 915
(2008/09/20)
-
- Salicylaldimine ruthenium alkylidene complexes: Metathesis catalysts tuned for protic solvents
-
Tuning the electronic and steric environment of olefin metathesis catalysts with specialized ligands can adapt them to broader applications, including metathesis in aqueous solvents. Bidentate salicylaldimine ligands are known to stabilize ruthenium alkylidene complexes, as well as allow ringclosing metathesis in protic media. Here, we report the synthesis and characterization of exceptionally robust olefin metathesis catalysts bearing both bidentate salicylaldimine and N-heterocyclic carbene ligands, including a trimethylammonium-functionalized complex adapted for polar solvents. NMR spectroscopy and X-ray crystallographic analysis confirm the structures of the complexes. Although the N-heterocyclic carbene-salicylaldimine ligand combination limits the activity of these catalysts in non-polar solvents, this pairing enables efficient ring-closing metathesis of both dienes and enynes in methanol and methanol/water mixtures under air.
- Binder, Joseph B.,Guzei, Ilia A.,Raines, Ronald T.
-
p. 395 - 404
(2008/02/07)
-
- Olefin metathesis in homogeneous aqueous media catalyzed by conventional ruthenium catalysts
-
(Chemical Equation Presented) Olefin metathesis in aqueous solvents is sought for applications in green chemistry and with the hydrophilic substrates of chemical biology, such as proteins and polysaccharides. Most demonstrations of metathesis in water, however, utilize exotic complexes. We have examined the performance of conventional catalysts in homogeneous water/organic mixtures, finding that the second-generation Hoveyda-Grubbs catalyst has extraordinary efficiency in aqueous dimethoxyethane and aqueous acetone. High (71-95%) conversions are achieved for ring-closing and cross metathesis of a variety of substrates in these solvent systems.
- Binder, Joseph B.,Blank, Jacqueline J.,Raines, Ronald T.
-
p. 4885 - 4888
(2008/03/14)
-
- METHOD FOR PRODUCING 3-AMINOMETHYLTETRAHYDROFURAN DERIVATIVE
-
An object of the present invention is to provide a process for producing a 3-cyanotetrahydrofuran derivative in a high yield from inexpensive industrial materials. According to the present invention, a 3-aminomethyltetrahydrofuran derivative is produced by preparing a 3-cyanotetrahydrofuran derivative in a high yield from an inexpensive and industrially easily available malic acid derivative, and reducing the cyano group of the 3-cyanotetrahydrofuran derivative.
- -
-
-
