- Low-pressure Selective Hydroformylation of 2,3- and 2,5-Dihydrofuran with a Rhodium Catalyst. Unexpected Influence of the Auxiliary Ligand Tris(o-t-butylphenyl) Phosphite
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Hydroformylation of 2,3- and 2,5-dihydrofuran has been achieved in excellent yields and good selectivities under mild conditions using 2(cod)2> and suitable auxiliary ligands (cod = cyclo-octa-1,5-diene).
- Polo, A.,Real, J.,Claver, C.,Castillon, S.,Bayon, J. C.
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- Effect of solvent nature on the catalytic hydroformylation of 2,3-dihydrofuran
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The effect of the solvent nature on the process of hydroformylation of 2,3-dihydrofuran in the presence of the phosphine-containing, complex Rh catalyst HRh(CO)(PPh3)3 has been studied. The influence of solvent polarity and basicity on the conversion of 2,3-dihydrofuran has been revealed, and the composition of tetrahydrofuran aldehydes and the selectivity of their formation have been determined.
- Wol'F,Vartanyan,Lapidus
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Read Online
- High-Temperature Synthesis of Carbon-Supported Bimetallic Nanocluster Catalysts by Enlarging the Interparticle Distance
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Supported bimetallic nanoparticle catalysts with small size have attracted wide research attention in catalysis but are difficult to synthesize because high-temperature annealing required for alloying inevitably accelerates metal sintering and leads to larger particles. Here, we report a simple and scalable critical interparticle distance method for the synthesis of a family of bimetallic nanocluster catalysts with an average particle size of only 1.5 nm by using large-surface-area carbon black supports at high temperatures, which consist of 12 diverse combinations of 3 noble metals (Pt, Ru, and Rh) and 4 other metals (Cr, Fe, Zr, and Sn). In this strategy, high-temperature treatments ensure the formation of alloyed bimetallic nanoparticles and enlargement of the interparticle distance on high-surface-area supports significantly suppresses metal sintering. The prepared ultrafine Pt2Sn and RuSn nanocluster catalysts exhibited enhanced performance in catalyzing the synthesis of aromatic secondary amines and the selective hydrogenation of furfural, respectively.
- Zuo, Lu-Jie,Xu, Shi-Long,Wang, Ao,Yin, Peng,Zhao, Shuai,Liang, Hai-Wei
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supporting information
p. 2719 - 2723
(2022/02/16)
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- Intermolecular C-O Bond Formation with Alkoxyl Radicals: Photoredox-Catalyzed α-Alkoxylation of Carbonyl Compounds
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Due to the high reactivity of alkoxyl (RO·) radicals and their propensity to easily undergo β-scission or Hydrogen Atom Transfer (HAT) reactions, intermolecular alkoxylations involving RO· radicals are barely described. We report herein for the first time the efficient intermolecular trapping of alkoxyl radicals by silyl enol ethers. This photoredox-mediated protocol enables the introduction of both structurally simple and more complex alkoxy groups into a wide range of ketones and amides.
- Banoun, Camille,Bourdreux, Flavien,Magnier, Emmanuel,Dagousset, Guillaume
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supporting information
p. 8926 - 8930
(2021/11/17)
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- Aqueous phase hydrogenation of furfural to tetrahydrofurfuryl alcohol over Pd/UiO-66
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A Pd/UiO-66 catalyst was synthesized with well-dispersed Pd nanoparticles. The obtained catalyst was tested in the hydrogenation of furfural to tetrahydrofurfuryl alcohol in various solvents, Water was found to be the most suitable solvent. Pd/UiO-66 exhibited much higher activity than Pd/SiO2 and Pd/γ-Al2O3, completely converting furfural to tetrahydrofurfuryl alcohol with 100% selectivity under mild conditions. The hydrogenation of C[dbnd]O moiety in tetrahydrofurfural was rate-determining step. Static adsorption measurement indicated that the adsorption of furfural on UiO-66 was significantly stronger than that on SiO2 or γ-Al2O3, suggesting that the adsorption play an important role in the gas-liquid-solid furfural hydrogenation reaction.
- Kogan, Victor M.,Liu, Ying-Ya,Sun, Zhichao,Wang, Anjie,Wang, Chunhua,Wang, Yao,Yu, Zhiquan
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- Selective hydrogenation of furfural to furfuryl alcohol over Pd/TiH2 catalyst
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In this work, the selective hydrogenation of furfural to furfuryl alcohol has been studied over Pd/TiH2 catalysts. The catalytic performances of several catalysts with different Pd loading (0.2–3% in weight) were discussed, among which a higher selectivity to furfuryl alcohol was obtained over 0.5Pd/TiH2 and it gave rise to a 73% furfural alcohol selectivity at complete conversion at 60 °C. The physicochemical properties of catalysts were well characterized by TEM, XRD, XPS, Raman, TPR and TPD, as well as in-situ DRIFT for the adsorption of the reactant. The size and the electronic state of Pd particles, and the surface defects of catalysts presented significant influence on the catalytic performance. The furfural is preferentially adsorbed with its C=O bond on the boundary of Pd particle and TiH2 support, leading to the high selectivity to furfuryl alcohol.
- Wang, Zhuangqing,Wang, Xinchao,Zhang, Chao,Arai, Masahiko,Zhou, Leilei,Zhao, Fengyu
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- Application of organic amine additive in synthesis of fluorescent dye intermediate through olefin hydroformylation reaction
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The invention discloses application of an organic amine additive in synthesis of a fluorescent dye intermediate through olefin hydroformylation reaction, and the application comprises the following steps: S1, the structure of the additive involved in the patent takes a nitrogen atom as a center, and three substituent groups linked with the nitrogen atom are alkyl groups or aromatic groups; and S2, in the hydroformylation reaction process, very few additives are introduced into the reaction system. The activity of a rhodium-aryl phosphine catalyst and the chemical selectivity of a product aldehyde can be obviously improved by using proper types and quantity of additives. The organic amine additive has the characteristics that compared with other types of additives reported in the literature, the organic amine additive can better regulate and control the activity of a rhodium-aryl phosphine catalyst and greatly improve the chemical selectivity of the product aldehyde, the organic amine additive provided by the invention can overcome the defects of other types of additives reported in the literature, and the cost of hydroformylation industrial production of various olefins is reduced.
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Paragraph 0015-0023
(2021/07/31)
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- Site- And enantiodifferentiating C(sp3)-H oxidation enables asymmetric access to structurally and stereochemically diverse saturated cyclic ethers
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A manganese-catalyzed site- and enantiodifferentiating oxidation of C(sp3)-H bonds in saturated cyclic ethers has been described. The mild and practical method is applicable to a range of tetrahydrofurans, tetrahydropyrans, and medium-sized cyclic ethers with multiple stereocenters and diverse substituent patterns in high efficiency with extremely efficient site- and enantiodiscrimination. Late-stage application in complex biological active molecules was further demonstrated. Mechanistic studies by combined experiments and computations elucidated the reaction mechanism and origins of stereoselectivity. The ability to employ ether substrates as the limiting reagent, together with a broad substrate scope, and a high level of chiral recognition, represent a valuable demonstration of the utility of asymmetric C(sp3)-H oxidation in complex molecule synthesis.
- Liu, Lei,Sun, Shutao,Yang, Yiying,Zhang, Dongju,Zhao, Ran
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supporting information
p. 19346 - 19353
(2020/12/01)
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- Selective hydrogenation of aromatic furfurals into aliphatic tetrahydrofurfural derivatives
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Tetrahydrofurfural (THFF) and 5-hydroxymethyltetrahydro-2-furaldehyde (5-HMTHFF) are important chemicals. Synthesis of THFF and 5-HMTHFF from the selective hydrogenation of furfural (FF) and 5-hydroxymethylfurfural (HMF) is highly desirable. However, it is a great challenge to hydrogenate furanyl rings while keeping CO intact. Herein, we found that Pd/LDH-MgAl-NO3 could efficiently catalyze the hydrogenation of FF to THFF and HMF to 5-HMTHFF in water. At near complete conversion of FF and HMF, the selectivities of THFF and 5-HMTHFF could reach 92.6% and 83.7%, respectively. A series of control experiments showed that both the LDH-MgAl-NO3 support and water solvent played an important role in the unusual performance of the catalytic system. The hydrogenation of the furanyl ring occurred on the surface of Pd. Water prohibited the hydrogenation of the CO group, and the special nature of LDH-MgAl-NO3 prevented hydrogenation of the CO group on the support by the hydrogen spillover. Thus, the furanyl ring was selectively hydrogenated, and high selectivity of the desired product was successfully achieved. As far as we know, efficient hydrogenation of FF to THFF or HMF to 5-HMTHFF has not been reported. This work opens the way to selectively hydrogenate the furanyl ring while keeping CO in the same molecule unchanged. This journal is
- Chen, Bingfeng,Han, Buxing,Li, Shaopeng,Liu, Huizhen,Shen, Xiaojun,Wang, Yanyan,Yang, Youdi
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supporting information
p. 4937 - 4942
(2020/11/07)
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- Controllable chemoselective hydrogenation of furfural by PdAg/C bimetallic catalysts under ambient operating conditions: An interesting Ag switch
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Hydrogenation of furfural to value-added chemical products is largely hindered by its multiple reaction pathways and complicated product distribution. Thus, to selectively achieve the desired products, catalysts with precise catalytic properties are highly required. Herein, a series of PdAg bimetallic nanoparticles (NPs) of similar size and tunable composition supported on activated carbon (Pd4Ag1/C, Pd2Ag1/C, Pd1Ag1/C and Pd2Ag3/C) were synthesized in a controlled manner and applied in the selective hydrogenation of furfural. Interestingly, an obvious composition-dependent catalytic performance was observed: upon incrementally increasing the proportion of Ag in PdAg NPs, the hydrogenation selectivity can transform from tetrahydrofurfuryl alcohol (sel. 94% for Pd4Ag1/C) to furfuryl alcohol (sel. 95% for Pd1Ag1/C) with nearly complete conversion (99%) of furfural. DFT calculations revealed that the adsorption free energy of in situ generated furfuryl alcohol on Pd(111) surface is inversely proportional correlated with the Ag content in PdAg bimetallic NPs, which accounts for the alteration of chemoselectivity. Importantly, the present study is the first demonstration of composition-induced selectivity reversal for the hydrogenation of furfural under ambient conditions (25 °C, 0.1 MPa H2).
- Wu, Zhi-Lei,Wang, Jian,Wang, Shuo,Zhang, Ya-Xin,Bai, Guo-Yi,Ricardez-Sandoval, Luis,Wang, Gui-Chang,Zhao, Bin
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supporting information
p. 1432 - 1442
(2020/03/11)
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- Synthesis of an Azaphosphatriptycene and Its Rhodium Carbonyl Complex
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A 10-aza-9-phosphatriptycene is accessible on a gram scale, in three laboratory steps from commercially available precursors. Infrared spectroscopy of a rhodium(I) carbonyl complex bearing this ligand reflects the weak σ-donor/strong π-acceptor character of the phosphine; the solid-state structure reveals moderate steric demand. This ligand supports highly active catalysts for the hydroformylation of cyclic alkenes.
- Cao, Yu,Napoline, Jonathan W.,Bacsa, John,Pollet, Pamela,Soper, Jake D.,Sadighi, Joseph P.
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p. 1868 - 1871
(2019/05/16)
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- Hydroformylation of unsaturated esters and 2,3-dihydrofuran under solventless conditions at room temperature catalysed by rhodium: N-pyrrolyl phosphine catalysts
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Rhodium complexes of the type HRh(CO)L3 (where L is an N-pyrrolyl phosphine, such as P(NC4H4)3, PPh(NC4H4)2, or PPh2(NC4H4)) were applied in the hydroformylation of less reactive unsaturated substrates, namely allyl acetate, butyl acrylate, methyl acrylate, 2,3-dihydrofuran and vinyl acetate. Even at room temperature, these catalysts enabled complete substrate conversion and high chemoselectivity towards the corresponding aldehydes. High conversion of vinyl acetate (88% in 6 h) to the branched aldehyde was obtained with HRh(CO)[P(NC4H4)3]3 at 25 °C. An increase of the turnover frequency, TOF, up to 2000 mol mol-1 h-1 was achieved in this reaction under 20 bar of syngas (H2/CO = 1) at 80 °C. The introduction of chiral phosphines, BINAP or Ph-BPE, to this system resulted in the production of a branched aldehyde with enantioselectivity, ee, up to 44 and 81%, respectively. High activity combined with high enantioselectivity was achieved due to the formation of the mixed rhodium hydrides HRh(CO)[P(NC4H4)3](BINAP) and HRh(CO)[P(NC4H4)3](Ph-BPE), identified by the NMR method.
- Alsalahi,Trzeciak
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p. 16990 - 16999
(2019/11/14)
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- Biomass-derived phosphorus-doped carbon materials as efficient metal-free catalysts for selective aerobic oxidation of alcohols
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Heteroatom-doped carbon materials (HDCMs) with abundant active functional groups and stable structural characteristics are promising catalysts for eco-friendly metal-free catalysis. In this work, phosphorus-doped carbon materials with a highly porous structure and extremely high surface area (>1600 m2 g-1) were successfully prepared via a convenient and scalable strategy using easily available soluble starch and phosphoric acid, which are expected to show good performance in mass-transfer and thus promote the catalytic process. As expected, the as-prepared PC-700 catalyst showed remarkable catalytic performance in aerobic oxidation of benzyl alcohol with a higher TOF value than other previously reported heteroatom-doped carbon catalysts. It also exhibited great tolerance for various substrates, including aromatic, alicyclic, heterocyclic, and aliphatic alcohols. On the basis of the related characterization studies and experimental results, it was proved that the P-O-C species and the defects caused by P-O species doping in the PC-700 catalyst are the active sites for aerobic oxidation. A unique mechanism was proposed for the catalytic process, which is different from that of N-doped graphene and graphene oxide catalyzed reactions that follow a free radical mechanism. In addition, the recycling test and characterization of the reused catalyst indicate that the PC-700 shows extraordinary performance in terms of both recyclability and stability and retains high reactivity even after eight cycles.
- Hu, Xiwei,Fan, Mengying,Zhu, Yangyang,Zhu, Qian,Song, Qiang,Dong, Zhengping
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p. 5274 - 5283
(2019/10/11)
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- Rhodium-catalysed vinyl 1,4-conjugate addition coupled with Sharpless asymmetric dihydroxylation in the synthesis of the CDE ring fragment of pectenotoxin-4
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Our synthesis of the CDE ring fragment of pectenotoxin-4 utilised two key steps to make the complex bicyclic ketal unit: (i) a rhodium-catalysed vinyl group 1,4-addition as the major C-C bond forming step; (ii) a stereoselective Sharpless Asymmetric Dihydroxylation (SAD) of the resulting 1,1-disubstituted homoallylic alcohol. Subsequent acid-catalysed cyclisation afforded the desired [5,6]-bicyclic ketal of the target molecule. This methodology was shown to be compatible with the desired E ring fragment 35 in order to construct the CDE fragment 37 of pectenotoxin-4.
- Richardson, Melodie S. W.,Tame, Christopher J.,Poole, Darren L.,Donohoe, Timothy J.
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p. 6336 - 6340
(2019/07/04)
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- Ru subnanoparticles on N-doped carbon layer coated SBA-15 as efficient Catalysts for arene hydrogenation
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The N-doped carbon layer coated SBA-15 support has been accomplished via a pyrolysis process. The ultra-low loading Ru nanoparticles (ca. 0.1 wt.%) was incorporated into the support by impregnation and the sequential reduction. The images of HAADF-STEM revealed that the Ru particles with sub-1-nm size (0.2-0.7 nm) were uniformly dispersed on the support. The ultrafine Ru particles displayed the excellent activity for the hydrogenation of olefins, arenes, phenol derivatives and heteroarenes in aqueous phase. The aliphatic or alicyclic compounds were produced selectively without the hydrogenolysis of C–O and C–N bonds. The high turnover frequency (TOF) values can reach up to 10,000 h?1. Notably, the activity of these catalysts improved dramatically with decreasing the sizes of Ru particles. Meanwhile, the N-doped carbon layer coating endowed the high stability of the Ru catalysts and prevented the leaching of the Ru species owning to the strong interaction between doped-N atoms and the ultrafine Ru particles. Overall, this work provides a highly attractive strategy to construct the supported sub-1-nm Ru particles utilized for the aqueous hydrogenation.
- Qian, Wei,Lin, Lina,Qiao, Yunxiang,Zhao,Xu, Zichen,Gong, Honghui,Li,Chen,Huang, Rong,Hou, Zhenshan
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- Surface-modified Pd-based catalyst, and preparation method and application thereof
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The invention discloses a surface-modified Pd-based catalyst, and a preparation method and application thereof. The preparation method comprises the following steps: (1) mixing a palladium salt and asilane coupling agent for coordination to obtain surface-modified palladium salt colloid particles; and (2) reacting the surface-modified palladium salt colloidal particles obtained in the step (1) with a carrier in an organic solvent to obtain the surface-modified Pd-based catalyst. The catalyst has a stable structure, and a catalytic hydrogenation reaction has the characteristic of high-selectivity cyclic hydrogenation.
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Paragraph 0045-0048; 0052-0054; 0058-0060; 0064-0066; 0070
(2020/01/03)
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- Atomic-layer-deposition-formed sacrificial template for the construction of an MIL-53 shell to increase selectivity of hydrogenation reactions
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We developed a method for using atomic layer deposition (ALD)-formed layers of Al2O3 as a sacrificial template to generate MIL-53(Al). The MOF shell in the CeO2/Pd@MIL-53(Al) configuration not only stabilized the Pd nanoparticles, but also regulated the selectivity of the hydrogenation of unsaturated aldehydes. This work represents the first demonstration of ALD-formed layers of metal oxides serving as sacrificial templates in the design of MOF-shell-based sandwich-type structures.
- Xu, Tiantian,Sun, Kai,Gao, Daowei,Li, Cuncheng,Hu, Xun,Chen, Guozhu
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supporting information
p. 7651 - 7654
(2019/07/04)
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- A preparation method of tetrahydrofurfuryl alcohol (by machine translation)
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The present invention discloses a certain temperature and hydrogen under pressure, the two containing Pd and Ru metal supported double-center catalyst preparation of tetrahydrofurfuryl alcohol furfural liquid-phase hydrogenation method, wherein the selectivity of tetrahydrofurfuryl alcohol is higher than 99%. The invention also discloses the supported double-center catalyst and its preparation method. The invention has the mild reaction conditions, the catalytic activity is high, the selectivity of the products and the like. (by machine translation)
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Paragraph 0050; 0051; 0065
(2019/06/27)
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- Doping Pd/SiO2 with Na+: Changing the reductive etherification of CO to furan ring hydrogenation of furfural in ethanol
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The production of biofuels and chemicals by hydrogenation of furfural has attracted much attention recently. Herein the effect of Na+ doping on the catalytic performance of Pd/SiO2 in hydrogenation and reductive-etherification of furfural in ethanol was systematically studied. Two Pd/SiO2 catalysts with and without the modification by Na+ were prepared by impregnation and calcination. Their catalytic properties were compared for the hydrogenation of furfural and furfural diethyl acetal under mild conditions. The silanol groups on Pd/SiO2 catalysed the acetalization of furfural and alcohol and the resulted acetal underwent hydrogenolysis on Pd nanoparticles (NPs) with an average particle size of 8 nm, leading to a moderate yield (~58%) of furfuryl ethyl ether. Doping Na+ on Pd/SiO2 led to the diminishing of silanol groups as well as strong interaction between Na+ and Pd NPs. No acetalization occurred on Na+ modified Pd/SiO2 due to the exchange of H+ of Si-OH with Na+, thus the reductive etherification of CO group in furfural was completely inhibited. Meanwhile the hydrogenation of furan-ring over Na+ coordinated Pd NPs could proceed with very high selectivity (>90%) forming tetrahydrofurfural in high yield. Kinetics study on the hydrogenation of furfural diethyl acetal over Pd/SiO2 and Na+ doped Pd/SiO2 suggested that the Na+ greatly impeded the hydrogenolysis of C-O-C bond of acetal, while the hydrogenation of the furan ring took place selectively.
- Long, Yinshuang,Wang, Yun,Wu, Haihong,Xue, Teng,Wu, Peng,Guan, Yejun
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p. 25345 - 25350
(2019/08/28)
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- Boosting the hydrolytic stability of phosphite ligand in hydroformylation by the construction of superhydrophobic porous framework
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The development of a catalyst that delivers high activities and selectivities with excellent durability is of great importance. Numerous efficient catalysts suffer from the inherent hydrolysis liabilities, plaguing their practical applications. Herein, we show that this challenge can be tackled by constructing them into superhydrophobic porous frameworks, as exemplified by a water-sensitive phosphite ligand, tris(2-tert-butylphenyl) phosphite. The efficiency and long-term stability of the developed system are remarkably high in the hydroformylation of internal olefins after metalation with Rh species, superior to the corresponding homogeneous analogues. The significantly boosted hydrolytic stability allows for catalytic transformations using water as a green solvent, which not only facilitates the isolation of the products, but also furnishes the aldehydes with higher regioselectivities for the desired linear form in comparison with that operated under benchmark conditions using toluene as a reaction medium. Given these promising results, we anticipate the strategy advanced herein will form the basis for constructive perspectives in the enhancement of the water resistance of catalysts and the development of high performance hydroformylation catalysts.
- Tang, Yongquan,Dong, Ke,Wang, Sai,Sun, Qi,Meng, Xiangju,Xiao, Feng-Shou
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- Chiral Diaryliodonium Phosphate Enables Light Driven Diastereoselective α-C(sp3)-H Acetalization
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C(sp3)-H bond functionalization has emerged as a robust tool enabling rapid construction of molecular complexity from simple building blocks, and the development of asymmetric versions of this reaction creates a powerful methodology to access enantiopure sp3-rich materials. Herein, we report the stereoselective functionalization of C(sp3)-H bonds of cyclic ethers employing a photochemically active diaryliodonium salt in combination with an anionic phase-transfer catalyst. The synthetic strategy outlined herein allows for regio- and stereochemical control in the α-C-H acetalization of furans and pyrans using alcohol nucleophiles, thus providing the ability to control the configuration at the stereogenic exocyclic acetal carbon.
- Ye, Baihua,Zhao, Jie,Zhao, Ke,McKenna, Jeffrey M.,Toste, F. Dean
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supporting information
p. 8350 - 8356
(2018/07/14)
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- Multicomponent Pt-Based Zigzag Nanowires as Selectivity Controllers for Selective Hydrogenation Reactions
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The selective hydrogenation of α, β-unsaturated aldehyde is an extremely important transformation, while developing efficient catalysts with desirable selectivity to highly value-added products is challenging, mainly due to the coexistence of two conjugated unsaturated functional groups. Herein, we report that a series of Pt-based zigzag nanowires (ZNWs) can be adopted as selectivity controllers for α, β-unsaturated aldehyde hydrogenation, where the excellent unsaturated alcohol (UOL) selectivity (>95%) and high saturated aldehyde (SA) selectivity (>94%) are achieved on PtFe ZNWs and PtFeNi ZNWs+AlCl3, respectively. The excellent UOL selectivity of PtFe ZNWs is attributed to the lower electron density of the surface Pt atoms, while the high SA selectivity of PtFeNi ZNWs+AlCl3 is due to synergy between PtFeNi ZNWs and AlCl3, highlighting the importance of Pt-based NWs with precisely controlled surface and composition for catalysis and beyond.
- Bai, Shuxing,Bu, Lingzheng,Shao, Qi,Zhu, Xing,Huang, Xiaoqing
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supporting information
p. 8384 - 8387
(2018/06/29)
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- Exploration of Pyrrolobenzodiazepine (PBD)-Dimers Containing Disulfide-Based Prodrugs as Payloads for Antibody-Drug Conjugates
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A number of cytotoxic pyrrolobenzodiazepine (PBD) monomers containing various disulfide-based prodrugs were evaluated for their ability to undergo activation (disulfide cleavage) in vitro in the presence of either glutathione (GSH) or cysteine (Cys). A good correlation was observed between in vitro GSH stability and in vitro cytotoxicity toward tumor cell lines. The prodrug-containing compounds were typically more potent against cells with relatively high intracellular GSH levels (e.g., KPL-4 cells). Several antibody-drug conjugates (ADCs) were subsequently constructed from PBD dimers that incorporated selected disulfide-based prodrugs. Such HER2 conjugates exhibited potent antiproliferation activity against KPL-4 cells in vitro in an antigen-dependent manner. However, the disulfide prodrugs contained in the majority of such entities were surprisingly unstable toward whole blood from various species. One HER2-targeting conjugate that contained a thiophenol-derived disulfide prodrug was an exception to this stability trend. It exhibited potent activity in a KPL-4 in vivo efficacy model that was approximately three-fold weaker than that displayed by the corresponding parent ADC. The same prodrug-containing conjugate demonstrated a three-fold improvement in mouse tolerability properties in vivo relative to the parent ADC, which did not contain the prodrug.
- Pei, Zhonghua,Chen, Chunjiao,Chen, Jinhua,Cruz-Chuh, Josefa Dela,Delarosa, Reginald,Deng, Yuzhong,Fourie-O'Donohue, Aimee,Figueroa, Isabel,Guo, Jun,Jin, Weiwei,Khojasteh, S. Cyrus,Kozak, Katherine R.,Latifi, Brandon,Lee, James,Li, Guangmin,Lin, Eva,Liu, Liling,Lu, Jiawei,Martin, Scott,Ng, Carl,Nguyen, Trung,Ohri, Rachana,Lewis Phillips, Gail,Pillow, Thomas H.,Rowntree, Rebecca K.,Stagg, Nicola J.,Stokoe, David,Ulufatu, Sheila,Verma, Vishal A.,Wai, John,Wang, Jing,Xu, Keyang,Xu, Zijin,Yao, Hui,Yu, Shang-Fan,Zhang, Donglu,Dragovich, Peter S.
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p. 3979 - 3996
(2018/08/03)
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- Facile synthesis of furfuryl ethyl ether in high yield: Via the reductive etherification of furfural in ethanol over Pd/C under mild conditions
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The one-pot synthesis of furfuryl ethyl ether (FEE) over Pd nanoparticles supported on TiO2, Al2O3, SiO2, and active carbon via the catalytic reductive etherification of furfural in ethanol was systematically studied. The Pd nanoparticles supported on SiO2, TiO2 and active carbon are all active for this novel process under mild reaction conditions, with Pd/C showing the highest selectivity to FEE. The effects of palladium loading, reaction temperature, and hydrogen pressure on the activity and selectivity of Pd/C have been investigated in detail. The results demonstrate that suitable Pd amount, low reaction temperature of about 60 °C, and low H2 pressure of about 0.3 MPa are favorable for the formation of the desired ether product. Under the optimized conditions, an unprecedented high yield of up to 81% of FEE was firstly obtained with the major by-products being furfuryl alcohol and 2-methyltetrahydrofuran. Compared with the conventional hydrogenation-etherification route via furfural alcohol as a reaction intermediate, the reductive etherification shows significant advantage in product yield because of its much lower reaction temperature that is required.
- Wang, Yun,Cui, Qianqian,Guan, Yejun,Wu, Peng
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p. 2110 - 2117
(2018/05/24)
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- The selective hydrogenation of furfural over supported palladium nanoparticle catalysts prepared by sol-immobilisation: Effect of catalyst support and reaction conditions
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The selective hydrogenation of bio-derived furfural was investigated under mild conditions using a series of supported palladium catalysts prepared by a sol-immobilisation technique. Catalysts using alumina and titania supports were more selective towards tetrahydrofurfuryl alcohol. The catalytic activity of 1.19% Pd/TiO2 was evaluated under different reaction conditions and higher selectivity towards tetrahydrofurfuryl alcohol was observed when using 2-propanol as a solvent, and the yield of tetrahydrofurfuryl alcohol decreased as reaction temperature increased. The performance of the Pd catalyst was enhanced by the addition of Pt and a 95% yield of tetrahydrofurfuryl alcohol was achieved. The catalysts were characterised using a range of techniques, and the synergistic effect of adding Pt to Pd was due to an electronic promotional effect.
- Albilali, Reem,Douthwaite, Mark,He, Qian,Taylor, Stuart H.
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p. 252 - 267
(2018/01/17)
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- Backbone-Modified Bisdiazaphospholanes for Regioselective Rhodium-Catalyzed Hydroformylation of Alkenes
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A series of tetraaryl bisdiazaphospholane (BDP) ligands were prepared varying the phosphine bridge, backbone, and substituents in the 2- and 5-positions of the diazaphospholane ring. The parent acylhydrazine backbone was transformed to an alkylhydrazine via a borane reduction procedure. These reduced ligands contained an all sp3 hybridized ring mimicking the all sp3 phospholane of (R,R)-Ph-BPE, a highly selective ligand in asymmetric hydroformylation. The reduced bisdiazaphospholane (red-BDP) ligands were shown crystallographically to have an increased C-N-N-C torsion angle - this puckering resembles the structure of (R,R)-Ph-BPE and has a dramatic influence on regioselectivity in rhodium catalyzed hydroformylation. The red-BDPs demonstrated up to a 5-fold increase in selectivity for the branched aldehyde compared to the acylhydrazine parent ligands. This work demonstrates a facile procedure for increased branched selectivity from the highly active and accessible class of BDP ligands in hydroformylation.
- Wildt, Julia,Brezny, Anna C.,Landis, Clark R.
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p. 3142 - 3151
(2017/09/05)
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- Stereocontrolled Synthesis of a Possible Stereoisomer of Laurenidificin and a Formal Total Synthesis of (+)-Aplysiallene Featuring a Stereospecific Ring Contraction
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We report a highly stereocontrolled total synthesis of one of the possible stereoisomers of laurenidificin. Highlights of the synthesis include the formation of the 2,6-dioxabicyclo[3.3.0]octane framework by a stereospecific bromolactonization-α-bromination-ring contraction sequence, followed by a stereoselective propargylation, an insertion of the Z-enyne side chain by a hydroindation/cross coupling reaction, and ethylation at C13 with an organocuprate reagent. While the synthetic compound was not identical to the natural product, the absolute stereochemistry of the natural product was proposed on the basis of NMR analyses. Moreover, a formal total synthesis of (+)-aplysiallene was achieved by extending the ring contraction strategy. (Chemical Equation Presented).
- Kobayashi, Shoji,Yokoi, Taiki,Inoue, Tomoharu,Hori, Yutaka,Saka, Tomoaki,Shimomura, Taiki,Masuyama, Araki
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p. 1484 - 1498
(2016/03/01)
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- PIPERIDINE ISOXAZOLE AND ISOTHIAZOLE OREXIN RECEPTOR ANTAGONISTS
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The present invention is directed to piperidine isoxazole and isothiazole orexin compounds which are antagonists of orexin receptors. The present invention is also directed to uses of the compounds described herein in the potential treatment or prevention of neurological and psychiatric disorders and diseases in which orexin receptors are involved. The present invention is also directed to compositions comprising these compounds. The present invention is also directed to uses of these compositions in the prevention or treatment of such diseases in which orexin receptors are involved.
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Page/Page column 87-88
(2016/05/19)
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- NOVEL DIHYDROPYRIDOISOQUINOLINONES AND PHARMACEUTICAL COMPOSITIONS THEREOF FOR THE TREATMENT OF INFLAMMATORY DISORDERS
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A compound according to Formula (I): wherein R1, LA, CyA, RA, R2, R3, and R4 are as described herein. The present invention relates to novel compounds according to Formula I that antagonize GPR84, a G-protein-coupled receptor that is involved in inflammatory conditions, and methods for the production of these novel compounds, pharmaceutical compositions comprising these compounds, and methods for the prevention and/or treatment of inflammatory conditions, pain, neuroinflammatory conditions, neurodegenerative conditions, infectious diseases, autoimmune diseases, endocrine and/or metabolic diseases, cardiovascular diseases, leukemia, and/or diseases involving impairment of immune cell functions by administering a compound of the invention.
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Paragraph 0300
(2016/11/14)
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- Difluorocyclobutylacetylenes as positive allosteric modulators of mGluR5 with reduced bioactivation potential
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Schizophrenia is a serious illness that affects millions of patients and has been associated with N-methyl-D-aspartate receptor (NMDAR) hypofunction. It has been demonstrated that activation of metabotropic glutamate receptor 5 (mGluR5) enhances NMDA receptor function, suggesting the potential utility of mGluR5 positive allosteric modulators (PAMs) in the treatment of schizophrenia. Herein we describe the optimization of an mGluR5 PAM by replacement of a phenyl with aliphatic heterocycles and carbocycles as a strategy to reduce bioactivation in a biaryl acetylene chemotype. Replacement with a difluorocyclobutane followed by further optimization culminated in the identification of compound 32, a low fold shift PAM with reduced bioactivation potential. Compound 32 demonstrated favorable brain uptake and robust efficacy in mouse novel object recognition (NOR) at low doses.
- Degnan, Andrew P.,Maxwell, Darrell,Balakrishnan, Anand,Brown, Jeffrey M.,Easton, Amy,Gulianello, Michael,Hanumegowda, Umesh,Hill-Drzewi, Melissa,Miller, Regina,Santone, Kenneth S.,Senapati, Arun,Shields, Eric E.,Sivarao, Digavalli V.,Westphal, Ryan,Whiterock, Valerie J.,Zhuo, Xiaoliang,Bronson, Joanne J.,Macor, John E.
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supporting information
p. 5871 - 5876
(2016/12/06)
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- ALKYNE SUBSTITUTED QUINAZOLINE COMPOUND AND METHODS OF USE
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The invention provides alkyne substituted quinazoline compounds, such as compounds of the formula (I), which are irreversible ErbB kinase inhibitors. The compounds are useful in the treatment of diseases and disorders where ErbB kinase activity is implicated such as a hyperproliferative disorder (e.g., cancer).
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Paragraph 0121; 0122
(2016/02/21)
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- Simultaneous hydrogenation and acid-catalyzed conversion of the biomass-derived furans in solvents with distinct polarities
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Furfural and 5-hydroxymethylfurfural (HMF), the two typical biomass-derived furans, can be converted into biofuels and value-added chemicals via hydrogenation or acid catalysis or both. The potential competition between the hydrogenation and the catalyzed-conversion of HMF and furfural has been investigated with Pd/C and Amberlyst 70 as the catalysts at 170°C in various solvents. In water, the hydrogenation of HMF or the derivatives of HMF could take place, but the acid-catalyzed conversion of HMF to the diketones (2,5-hexanedione) was the dominant reaction pathway. On the contrary, with ethanol as the solvent, the full hydrogenation of HMF to 2,5-tetrahydrofurandimethanol was the dominant route, and the acid-catalyzed routes became insignificant. The efficiency for hydrogenation of HMF was much higher in ethanol than in water. As for furfural, its hydrogenation proceeded more efficiently in the polar solvents (i.e. ethanol, diethyl ether) than in non-polar solvents (i.e. toluene): a polar solvent tended to favor the hydrogenation of the furan ring in furfural over that of the carbonyl group in the same furfural.
- Hu, Xun,Kadarwati, Sri,Song, Yao,Li, Chun-Zhu
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p. 4647 - 4656
(2016/01/29)
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- Tetrahydrofuran compound, as well as hydrogenation catalyst and method of manufacturing same
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PROBLEM TO BE SOLVED: To provide a method for producing a tetrahydrofuran compound from a furan compound at high reaction rate in high yield and in highly selective manner even under low temperature.SOLUTION: There is provided a method for producing a tetrahydrofuran compound, the method comprising a step of bringing a furan compound having a specific substituent into contact with hydrogen to obtain a tetrahydrofuran compound represented by general formula (2) in the presence of a catalyst obtained by mixing a palladium compound with a metallic compound having at least one metal element belonging to groups V to IX on the periodic table as constituent elements and subjecting to reduction treatment. In the formula (2), Rrepresents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or hydroxymethyl group, and Rand Reach independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.
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Paragraph 0079
(2017/05/06)
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- Hydroformylation of dihydrofurans catalyzed by rhodium complex encapsulated hexagonal mesoporous silica
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HRh(CO)(PPh3)3 encapsulated hexagonal mesoporous silica (HMS) is found to be an efficient heterogeneous catalyst for the selective hydroformylation of 2,3-dihydrofuran (2,3DHF) and 2,5-dihydrofuran (2,5DHF). The Rh-complex encapsulated in situ in the organic phase of template inside the pores of HMS was found to act as nano phase reactors. Conversion of 2,3-DHF and 2,5-DHF and selectivity of the corresponding aldehydes were thoroughly investigated by studying the reaction parameters: catalyst amount, substrate concentration, partial as well as total pressure of CO and H2, and temperature. The selectivity for the formation of tetrahydrofuran-2-carbaldehyde (THF-2-carbaldehyde) from the hydroformylation of 2,3-DHF was found to be more than the selectivity of the formation of tetrahydrofuran-3-carbaldehyde (THF-3-carbaldehyde) from 2,5-DHF. The reaction paths are suggested and discussed for the selective formation of the corresponding aldehydes. The catalyst was elegantly separated and effectively recycled for six times.
- Khokhar, Munir D.,Shukla, Ram S.,Jasra, Raksh V.
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- Highly selective bisphosphine ligands for asymmetric hydroformylation of heterocyclic olefins
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The bisphosphine ligand 1c is highly efficient and selective for the asymmetric hydroformylation (AHF) of dihydrofuran and pyrrolines. The AHF of 2,3-dihydrofuran yielded the 2-carbaldehyde in up to 93% ee. The remarkable highest regioselectivity of 2,5-dihydrofuran was obtained to date up to 499 β-isomer/α-isomer with ligand 1c. Furthermore, the highest 96% and 92% ee values were accomplished using the same catalytic system in the AHF of N-Boc pyrroline 11 and 14.
- Zheng, Xin,Xu, Kun,Zhang, Xumu
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p. 1149 - 1152
(2015/02/19)
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- Synthesis and reactions of donor cyclopropanes: efficient routes to cis- and trans-tetrahydrofurans
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Abstract A detailed study on the synthesis and reactions of silylmethylcyclopropanes is reported. In their simplest form, these donor-only cyclopropanes undergo Lewis acid promoted reaction to give either cis- or trans-tetrahydrofurans, with the selectivity being reaction condition-dependant. The adducts themselves are demonstrated to be an important scaffold for structural diversification. The combination of a silyl-donor group in a donor-acceptor cyclopropane with novel acceptor groups is also discussed.
- Dunn, Jonathan,Dobbs, Adrian P.
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supporting information
p. 7386 - 7414
(2015/08/24)
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- FACTOR XIa INHIBITORS
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The present invention provides a compound of Formula (I) and pharmaceutical compositions comprising one or more said compounds, and methods for using said compounds for treating or preventing thromboses, embolisms, hypercoagulability or fibrotic changes. The compounds are selective Factor XIa inhibitors or dual inhibitors of Factor XIa and plasma kallikrein.
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Page/Page column 67
(2015/12/09)
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- Asymmetric Hydroformylation of Heterocyclic Olefins Mediated by Supramolecularly Regulated Rhodium-Bisphosphite Complexes
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Rhodium complexes derived from conformationally transformable α,ω-bisphosphite ligands combined with a suitable alkali metal BArF salt as a regulation agent (RA) provide high regio- and enantioselectivities in the asymmetric hydroformylation (AHF) of three heterocyclic olefins. The outcome of the AHF could be exquisitely regulated by choosing the appropriate RA with an increase in the ee, the reversal of the regioselectivity, or the complete suppression of one byproduct.
- Rovira, Laura,Vaquero, Mónica,Vidal-Ferran, Anton
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supporting information
p. 10397 - 10403
(2015/11/03)
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- Enantiopure narrow bite-angle P-OP ligands: Synthesis and catalytic performance in asymmetric hydroformylations and hydrogenations
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Herein is reported the preparation of a set of narrow bite-angle P-OP ligands the backbone of which contains a stereogenic carbon atom. The synthesis was based on a Corey-Bakshi-Shibata (CBS)-catalyzed asymmetric reduction of phosphomides. The structure of the resulting 1,1-P-OP ligands, which was selectively tuned through adequate combination of the configuration of the stereogenic carbon atom, its substituent, and the phosphite fragment, proved crucial for providing a rigid environment around the metal center, as evidenced by X-ray crystallography. These new ligands enabled very good catalytic properties in the Rh-mediated enantioselective hydrogenation and hydroformylation of challenging and model substrates (up to 99 % ee). Whereas for asymmetric hydrogenation the optimal P-OP ligand depended on the substrate, for hydroformylation, a single ligand was the highest-performing one for almost all studied substrates: it contains an R-configured stereogenic carbon atom between the two phosphorus ligating groups, and an S-configured 3,3′-diphenyl-substituted biaryl unit. Ligand design: Narrow-bite-angle P-OP ligands incorporating a stereogenic carbon atom in their backbone have been synthesized by Corey-Bakshi-Shibata (CBS)-catalyzed asymmetric reduction of the corresponding intermediates followed by O-phosphorylation. Rhodium complexes of these ligands provided very good catalytic performance in hydroformylations and hydrogenations (see scheme).
- Fernández-Pérez, Héctor,Benet-Buchholz, Jordi,Vidal-Ferran, Anton
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p. 15375 - 15384
(2016/02/18)
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- Easily accessible and highly tunable bisphosphine ligands for asymmetric hydroformylation of terminal and internal alkenes
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An efficient methodology for synthesizing a small library of easily tunable and sterically bulky ligands for asymmetric hydroformylation (AHF) has been reported. Five groups of alkene substrates have been tested with excellent conversions, moderate-to-excellent regio- and enantioselectivities. Among the best result of the reported literature, application of ligand 1 c in the highly selective AHF of the challenging substrate 2,5-dihydrofuran yielded almost one isomer in up to 99 % conversion along with enantiomeric excesses (ee) of up to 92 %. Highly enantioselective AHF of dihydropyrrole substrates is achieved using the same ligand, with up to 95 % ee and up to >1:50 β-isomer/α- isomer ratio. The simpler the better! An efficient method for the easy and tunable synthesis of a series of asymmetric hydroformylation (AHF) ligands from low-cost, commercially available starting materials has been reported. These ligands can give excellent conversions and moderate to excellent regio- and enantioselectivities for a broad range of mono- and disubstituted alkenes with a low catalyst loading (substrate-to-catalyst ratios (S/C) of 1000:1 to 3000:1).
- Xu, Kun,Zheng, Xin,Wang, Zhiyong,Zhang, Xumu
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p. 4357 - 4362
(2014/05/06)
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- Immobilized bisdiazaphospholane catalysts for asymmetric hydroformylation
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Condensation reactions of enantiopure bis-3,4-diazaphospholanes (BDPs) that are functionalized with carboxylic acids enable covalent attachment to bead and silica supports. Exposure of tethered BDPs to the hydroformylation catalyst precursor, Rh(acac)(CO)2, yields catalysts for immobilized asymmetric hydroformylation (iAHF) of prochiral alkenes. Compared with homogeneous catalysts, catalysts immobilized on Tentagel resins exhibit similarly high regioselectivity and enantioselectivity. When corrected for apparent catalyst loading, the activity of the immobilized catalysts approaches that of the homogeneous analogues. Excellent recyclability with trace levels of rhodium leaching are observed in batch and flow reactor conditions. Silica-bound catalysts exhibit poorer enantioselectivities.
- Adint, Tyler T.,Landis, Clark R.
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p. 7943 - 7953
(2014/06/23)
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- Total hydrogenation of furfural and 5-hydroxymethylfurfural over supported Pd-Ir alloy catalyst
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Hydrogenation of aqueous furfural was conducted with SiO 2-suported palladium-based bimetallic catalysts. The combination of palladium and iridium gave the best performance for the total hydrogenation to tetrahydrofurfuryl alcohol. Higher H2 pressure and lower reaction temperature were advantageous to suppress side reactions. The synergy between Pd and Ir in the hydrogenation catalysis is most remarkable for substituted furans as substrates. Furfural was first converted into furfuryl alcohol, which was further converted to tetrahydrofurfuryl alcohol. A small amount of tetrahydrofurfural was formed in the first step (~20% selectivity), and the subsequent hydrogenation of tetrahydrofurfural was much slower. The combined yield of tetrahydrofurfuryl alcohol and tetrahydrofurfural reached 98%. The yield of tetrahydrofurfuryl alcohol reached 94% with larger amount of catalyst. Total hydrogenation of 5-hydroxymethylfurfural was also possible using Pd-Ir/SiO2 catalyst. The performance of Pd-Ir/SiO2 catalyst was slightly changed by repeated uses, and the used catalyst can be regenerated by calcination and reduction at 573 K. Characterization results showed that Pd-Ir alloy particles with size of ≤4 nm were formed on the catalyst. Addition of Ir much increased the TOF values as compared with Pd/SiO2 with similar particle size, especially for C = O hydrogenation. One factor of higher activity of Pd-Ir/SiO2 than Pd/SiO2 can be the change of adsorption mode: Ir atom on the surface promotes the adsorption at C = O site, whereas the Pd surface strongly interacts with furan ring.
- Nakagawa, Yoshinao,Takada, Kana,Tamura, Masazumi,Tomishige, Keiichi
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p. 2718 - 2726
(2014/08/18)
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- Libraries of bisdiazaphospholanes and optimization of rhodium-catalyzed enantioselective hydroformylation
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Twelve chiral bis-3,4-diazaphospholane ligands and six alkene substrates (styrene, vinyl acetate, allyloxy-tert-butyldimethylsilane, (E)-1-phenyl-1,3- butadiene, 2,3-dihydrofuran, and 2,5-dihydrofuran) probe the influence of steric bulk on the activity and selectivity of asymmetric hydroformylation (AHF) catalysts. Reaction of an enantiopure bisdiazaphospholane tetraacyl fluoride with primary or secondary amines yields a small library of tetracarboxamides. For all six substrates, manipulation of reaction conditions and bisdiazaphospholane ligands enables state-of-the-art performance (90% or higher ee, good regioselectivity, and high turnover rates). For the nondihydrofuran substrates, the previously reported ligand, (S,S)-2, is generally most effective. However, optimal regio- and enantioselective hydroformylation of 2,3-dihydrofuran (up to 3.8:1 α-isomer/β-isomer ratio and 90% ee for the α-isomer) and 2,5-dihydrofuran (up to 1:30 α-isomer/β- isomer ratio and 95% ee for the β-isomer) arises from bisdiazaphospholanes containing tertiary carboxamides. Hydroformylation of either 2,3- or 2,5-dihydrofuran yields some of the β-formyl product. However, the absolute sense of stereochemistry is inverted. A stereoelectronic map rationalizes the opposing enantiopreferences
- Adint, Tyler T.,Wong, Gene W.,Landis, Clark R.
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p. 4231 - 4238
(2013/06/05)
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- Small bite-angle P-OP ligands for asymmetric hydroformylation and hydrogenation
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A series of small bite-angle phosphine-phosphite (P-OP) ligands have been synthesized by a two-step method. The key intermediate was prepared by an unprecedented asymmetric carbonyl reduction of a phosphamide using the CBS (Corey-Bakshi-Shibata) catalyst. The topology of these ligands (a configurationally stable stereogenic carbon with two heteroatom substituents) and their small bite-angle (created by the close proximity of the two ligating groups to the metal center) together provide a rigid asymmetric environment around this center, enabling high stereoselectivity in hydroformylations and hydrogenations of standard substrates.
- Fernandez-Perez, Hector,Benet-Buchholz,Vidal-Ferran, Anton
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supporting information
p. 3634 - 3637
(2013/08/23)
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- Highly selective asymmetric Rh-catalyzed hydroformylation of heterocyclic olefins
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A small family of new chiral hybrid, diphosphorus ligands, consisting of phosphine-phosphoramidites L1 and L2 and phosphine-phosphonites L3a-c, was synthesized for the application in Rh-catalyzed asymmetric hydroformylation of heterocyclic olefins. High-pressure (HP)-NMR and HP-IR spectroscopy under 5-10 bar of syngas has been employed to characterize the corresponding catalyst resting state with each ligand. Indole-based ligands L1 and L2 led to selective ea coordination, while the xanthene derived system L3c gave predominant ee coordination. Application of the small bite-angle ligands L1 and L2 in the highly selective asymmetric hydroformylation (AHF) of the challenging substrate 2,3-dihydrofuran (1) yielded the 2-carbaldehyde (3) as the major regioisomer in up to 68% yield (with ligand L2) along with good ees of up to 62%. This is the first example in which the asymmetric hydroformylation of 1 is both regio- and enantioselective for isomer 3. Interestingly, use of ligand L3c in the same reaction completely changed the regioselectivity to 3-carbaldehyde (4) with a remarkably high enantioselectivity of 91%. Ligand L3c also performs very well in the Rh-catalyzed asymmetric hydroformylation of other heterocyclic olefins. Highly enantioselective conversion of the notoriously difficult substrate 2,5-dihydrofuran (2) is achieved using the same catalyst, with up to 91% ee, concomitant with complete regioselectivity to the 3-carbaldehyde product (4) under mild reaction conditions. Interestingly, the Rh-catalyst derived from L3c is thus able to produce both enantiomers of 3-carbaldehyde 4, simply by changing the substrate from 1 to 2. Furthermore, 85% ee was obtained in the hydroformylation of N-acetyl-3-pyrroline (5) with exceptionally high regioselectivities for 3-carbaldehyde 8Ac (>99%). Similarly, an ee of 86% for derivative 8Boc was accomplished using the same catalyst system in the AHF of N-(tert-butoxycarbonyl)-3-pyrroline (6). These results represent the highest ees reported to date in the AHF of dihydrofurans (1, 2) and 3-pyrrolines (5, 6).
- Chikkali, Samir H.,Bellini, Rosalba,De Bruin, Bas,Van Der Vlugt, Jarl Ivar,Reek, Joost N. H.
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experimental part
p. 6607 - 6616
(2012/06/15)
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- Compounds and Their Use for Treatment of Amyloid Beta-Related Diseases
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The present invention relates to novel compounds of formula (I) and pharmaceutically acceptable salts thereof, pharmaceutical compositions comprising said compounds, processes for making said compounds, and their use as medicaments for treatment and/or prevention of Aβ-related diseases.
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Page/Page column 29
(2012/05/21)
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- Microwave promoted regeneration of carbonyl compounds from oximes using N, N-dichloro poly(styrene-co-divinylbenzene)sulphonamide resin
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An efficient, economically viable and operationally simple method was developed for deoximation of oximes (of ketones and aldehydes) to their corresponding carbonyl compounds using polymer beads of N, N-dichloro poly(styrene-co-divinylbenzene)sulphonamide resin. Polymeric reagent offered speedy conversion and substantial yields of products under mild condition and is recyclable. Deoximation was monitored by the use of 13C NMR.
- Beldar,Sharma, Mamta
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experimental part
p. 288 - 292
(2012/02/01)
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- Green and chemoselective oxidation of alcohols with hydrogen peroxide: A comparative study on Co(II) and Co(III) activity toward oxidation of alcohols
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Two new cobalt (II) and cobalt (III) complexes of a terpyridine based ligand, (4′-(2-thienyl)-2,2′;6′,2″-terpyridine (L)), were synthesized. Each complex has two units of the tridentate ligand. The complexes were fully characterized by spectroscopic methods as well as CHN analysis. Moreover, their solid state structures were determined by single crystal X-ray diffraction. The cobaltous complex has the formula [Co(L) 2](NO3)2·2CH3OH·H 2O (1), whereas the cobaltic complex shows the formula [Co(L) 2](NO3)3·2CH3OH (2). Both complexes were tested as homogenous catalysts for the oxidation of a variety of aliphatic and aromatic alcohols utilizing aqueous hydrogen peroxide in water media. The Co(II) complex showed more activity in comparison with its isostructural Co(III) species. The results show that the aromatic alcohols were oxidized with higher conversions and selectivity compared to the aliphatic substrates, possibly due to their conjugation systems which thermodynamically stabilized the carbonyl products.
- Nemati Kharat, Ali,Bakhoda, Abolghasem,Tamaddoni Jahromi, Bahareh
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scheme or table
p. 2768 - 2775
(2011/12/13)
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- Zirconium(IV)- and hafnium(IV)-catalyzed highly enantioselective epoxidation of homoallylic and bishomoallylic alcohols
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In this report, zirconium(IV)- and hafnium(IV)-bishydroxamic acid complexes were utilized in the highly enantioselective epoxidation of homoallylic alcohols and bishomoallylic alcohols, which used to be quite difficult substrates for other types of asymmetric epoxidation reactions. The performance of the catalyst was improved by adding polar additive and molecular sieves. For homoallylic alcohols, the reaction could provide epoxy alcohols in up to 83% yield and up to 98% ee, while, for bishomoallylic alcohols, up to 79% yield and 99% ee of epoxy alcohols rather than cyclized tetrahydrofuran compounds could be obtained in most cases.
- Li, Zhi,Yamamoto, Hisashi
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scheme or table
p. 7878 - 7880
(2010/08/04)
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- Highly enantioselective hydroformylation of dihydrofurans catalyzed by hybrid phosphine-phosphonite rhodium complexes
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Unprecedented regio- and enantioselectivities (>91%) are reported for the Rh-catalyzed asymmetric hydroformylation of 2,3- and 2,5-dihydrofuran using tunable hybrid phosphine-phosphonite ligands.
- Chikkali, Samir H.,Bellini, Rosalba,Berthon-Gelloz, Guillaume,Van Der Vlugt, Jarl Ivar,De Bruin, Bas,Reek, Joost N. H.
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supporting information; experimental part
p. 1244 - 1246
(2010/06/15)
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- Highly efficient rhodium catalysts for the asymmetric hydroformylation of vinyl and allyl ethers using C1-symmetrical diphosphite ligands
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Here, we describe the successful application of novel glucofuranose-derived 1,3-diphosphites in the rhodium-catalysed asymmetric hydroformylation of vinyl acetate, 2,5-dihydrofuran and 2,3-dihydrofuran. In the hydroformylation of vinyl acetate, total regioselectivity and high ee (up to 73%) were obtained. When 2,3- and 2,5-dihydrofuran were the substrates, total chemo- and regioselectivities were achieved together with ees up to 88%. These results correspond to the highest ee values reported to date in the asymmetric hydroformylation of these substrates. The HP-NMR studies of the [RhH(CO) 2(L)] species (L=15 and 17) demonstrated that both ligands coordinate to the Rh centre in an eq-eq fashion. The complex [RhH(CO)2(15)] was detected as a single isomer with characteristic features of eq-eq coordination. However, the broadening of the corresponding signals indicated that this species is rapidly interchanging in solution. In contrast, complex [RhH(CO) 2(17)] was detected as a mixture of two conformational isomers at low temperature due to the greater flexibility of the monocyclic backbone of this ligand.
- Gual, Aitor,Godard, Cyril,Castillon, Sergio,Claver, Carmen
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experimental part
p. 463 - 477
(2010/06/13)
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