1896-62-4Relevant articles and documents
Stereospecific alkyne reduction: Novel activity of old yellow enzymes
Mueller, Andre,Stuermer, Rainer,Hauer, Bernhard,Rosche, Bettina
, p. 3316 - 3318 (2007)
Old enzyme, new trick: An environmentally sustainable alternative for the regio-and stereoselective reduction of the alkyne bond is the biotransformation by "Old Yellow Enzyme" (OYE). This "old" enzyme, first isolated in 1932, catalyzes the trans-selective hydrogenation of the carbon-carbon triple bond under mild conditions. (Chemical Equation Presented).
Tuning the hydrogen donor/acceptor behavior of ionic liquids in Pd-catalyzed multi-step reactions
López-Vinasco, Angela M.,Guerrero-Ríos, Itzel,Favier, Isabelle,Pradel, Christian,Teuma, Emmanuelle,Gómez, Montserrat,Martin, Erika
, p. 56 - 61 (2015)
Palladium nanoparticles stabilized by thioether-phosphine ligands (1-3) were used as catalytic precursors in Heck-Mizoroki cross-coupling and CC reduction reactions in ionic liquids. The ionic liquid [EMI][MeHPO3] (A) exhibited an important hydrogen donor/acceptor behavior depending on the reaction conditions. Tandem or parallel pathways for C-C coupling and H-transfer reactions were observed, leading to the coupled product trans-4-phenyl-3-buten-2-one (I) and the corresponding reduced partner 4-phenylbutan-2-one (II) pointing to a molecular-like catalytic reactivity of the process. When the reaction was carried out under hydrogen pressure and low temperature, the reduction to II was inhibited by the presence of thioether-phosphine ligands.
Metal-Controlled Selective [3+2] Cyclization Reactions of Alkenyl Fischer Carbene Complexes and Allenes
Barluenga, Jose,Vicente, Ruben,Barrio, Pablo,Lopez, Luis A.,Tomas, Miguel
, p. 5974 - 5975 (2004)
Chromium alkenyl Fischer carbene complexes undergo selective [3+2] cyclization reactions to allenes in the presence of nickel(0) or rhodium(I) catalysts. Interestingly, the chemo- and regioselectivity of the process are entirely dependent on the nature of the metal. Copyright
Metalloporphyrin-catalyzed diastereoselective epoxidation of allyl-substituted alkenes
Chan, Wing-Kei,Wong, Man-Kin,Che, Chi-Ming
, p. 4226 - 4232 (2005)
By using [Mn(2,6-Cl2TPP)Cl] (1) as a catalyst and Oxone/H 2O2 as an oxidant, we have developed an efficient method for erythro-selective epoxidation of acyclic allyl-substituted alkenes, including allylic alcohols, amines, and esters. Up to 9:1 erythro selectivities for terminal allyllic alkenes could be achieved, which are significantly higher than that achieved using m-CPBA as an oxidant. In addition, the synthetic utilities of this epoxidation method were highlighted in stereoselective synthesis of key anti-HIV drug intermediates and epoxidation of glycals.
Stereospecific synthesis of phosphono-(1Z,3E)-dienyl compounds from β-phenyltelluro-vinylphosphonates and -vinylphosphine oxides
Braga, Antonio L.,Rhoden, Cristiano R.B.,Zeni, Gilson,Silveira, Claudio C.,Andrade, Leandro H.
, p. 35 - 40 (2003)
Phosphono-1,3-dienyl compounds 2 can be prepared by palladium cross-coupling reaction of β-phenyltelluro-vinylphosphonates or -vinylphosphine oxides with alkenes in the presence of a catalytic amount of PdCl2 and AcOAg as reoxidant agent at room temperature. The coupling reaction is stereospecific and the compounds 2 were obtained in good yields with total retention of configuration.
Highly dispersed nickel and palladium nanoparticle silica aerogels: Sol-gel processing of tethered metal complexes and application as catalysts in the Mizoroki-Heck reaction
Martinez, Sandra,Moreno-Manas, Marcial,Vallribera, Adelina,Schubert, Ulrich,Roig, Anna,Molins, Elies
, p. 1093 - 1097 (2006)
Highly dispersed Ni and Pd silica aerogels were prepared through sol-gel processes. They have been synthesized by tethering the metal to the silica matrix with the use of the complexing silanes AEAPTS [N-(aminoethyl)aminopropyl] trimethoxysilane or TRIAMIN [N-((aminoethyl)aminoethyl)aminopropyl] trimethoxysilane. The gels were dried with scCO2 to afford the aerogels. High metal dispersion and small particle sizes were observed through HRTEM and XRD measurements. The organic groups were removed by oxidation and/or pyrolysis. The Pd reduced aerogels containing 15-17% of palladium are good recoverable catalysts in the Mizoroki-Heck reaction. the Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2006.
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Ksander,McMurry
, p. 4691 (1976)
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An efficient Pd@Pro-GO heterogeneous catalyst for the α, β-dehydrogenation of saturated aldehyde and ketones
Pan, Gao-Fei,Wang, Zhe,Chang, Yi-Yuan,Hao, Yue,Wang, Yi-Chen,Xing, Rui-Guang
supporting information, (2021/12/30)
An Efficient Pd@Pro-GO heterogeneous catalyst was developed that can promote the α, β-dehydrogenation of saturated aldehyde and ketones in the yield of 73% ? 92% at mild conditions without extra oxidants and additives. Pd@Pro-GO heterogeneous catalyst was synthesized via two steps: firstly, the Pro-GO was obtained by the esterification reaction between graphene oxide (GO) and N-(tert-Butoxycarbonyl)-L-proline (Boc-Pro-OH), followed by removing the protection group tert-Butoxycarbonyl (Boc), which endowed the proline-functionalized GO with both the lewis acid site (COOH) and the bronsted base site (NH), besides, the pyrrolidine of proline also can form imine with aldehydes to activate these substrates; Second, palladium was dispersed on the proline-functionalized GO (Pro-GO) to obtained heterogeneous catalyst Pd@Pro-GO. Mechanistic studies have shown that the Pd@Pro-GO-catalyzed α,β-dehydrogenation of saturated aldehyde and ketones was realized by an improved heterogeneously catalyzed Saegusa oxidation reaction. Based on the obove characteristics, the Pd@Pro-GO will be widely used in the transition metal catalytic field.
Heterogeneous Isomerization for Stereoselective Alkyne Hydrogenation to trans-Alkene Mediated by Frustrated Hydrogen Atoms
Zhang, Weijie,Qin, Ruixuan,Fu, Gang,Zheng, Nanfeng
supporting information, p. 15882 - 15890 (2021/10/02)
Stereoselective production of alkenes from the alkyne hydrogenation plays a crucial role in the chemical industry. However, for heterogeneous metal catalysts, the olefins in cis-configuration are usually dominant in the products due to the most important and common Horiuti-Polanyi mechanism involved over the metal surface. In this work, through combined theoretical and experimental investigations, we demonstrate a novel isomerization mechanism mediated by the frustrated hydrogen atoms via the H2 dissociation at the defect on solid surface, which can lead to the switch in selectivity from the cis-configuration to trans-configuration without overhydrogenation. The defective Rh2S3 with exposing facet of (110) exhibits outstanding performance as a heterogeneous metal catalyst for stereoselective production of trans-olefins. With the frustrated hydrogen atoms at spatially separated high-valence Rh sites, the isolated hydrogen mediated cis-to-trans isomerization of olefins can be effectively conducted and the overhydrogenation can be completely inhibited. Furthermore, the bifunctional Rh-S/Pd nanosheets have been synthesized through the surface modification of Pd nanosheets with rhodium and sulfide. With the selective semihydrogenation of alkynes into cis-olefins catalyzed by the small surface PdSx ensembles, the bifunctional Rh-S/Pd nanosheets exhibit excellent activity and stereoselectivity in the one-pot alkyne hydrogenation into trans-olefin, which surpasses the most reported homogeneous and heterogeneous catalysts.
Piperlongumine derivative as well as preparation method and application thereof
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Paragraph 0033; 0040, (2021/01/28)
The invention discloses a Piperlongumine derivative as well as a preparation method and application thereof. The Piperlongumine derivative has the following structure: the Piperlongumine derivative provided by the invention contains a plurality of Michael addition receptor units, and the novel structure improves the electrophilicity, so that the Piperlongumine derivative has good protein targetingpotential, and the Piperlongumine derivative has a good inhibition effect on thioredoxin reductase; in an antitumor bioactive in-vitro screening experiment, the derivative also has a certain inhibition effect on the growth of tumor cells, and meanwhile, the derivative has an effect of promoting the generation of active oxygen in A549 human lung cancer cells.