- N-heterocyclic carbene coordinated heterogeneous Pd nanoparticles as catalysts for suzuki-miyaura coupling
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Palladium nanoparticle (Pd NP) catalysts immobilized in a polymer with an N-heterocyclic carbene (NHC) moiety (PICBNHC-Pd) have been developed, wherein the NHC moiety plays dual roles as a crosslinker and a ligand to activate the Pd NPs. The presence of both Pd NPs and NHC was confirmed by STEM/EDS and SR-MAS NMR analyses, respectively. This PICB-NHC-Pd catalyst showed excellent activity in the Suzuki-Miyaura coupling reaction without leaching of Pd. Excellent results were obtained in gram-scale synthesis, and catalyst recovery/reuse experiments were completed without loss of catalyst activity.
- Min, Hyemin,Miyamura, Hiroyuki,Kobayashi, Shu
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supporting information
p. 837 - 839
(2016/07/16)
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- Size of gold nanoparticles driving selective amide synthesis through aerobic condensation of aldehydes and amines
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Metal nanoparticles (NPs) have attracted much attention in many fields due to their intrinsic characteristics. It is generally accepted that smaller NPs (1.5-3 nm) are more active than larger NPs, and reverse cases are very rare. We report here the direct aerobic oxidative amide synthesis from aldehydes and amines catalyzed by polymer-incarcerated gold (Au) NPs. A unique correlation between imine/amide selectivity and size of NPs was discovered; Au-NPs of medium size (4.5-11 nm) were found to be optimal. High yields were obtained with a broad range of substrates, including primary amines. Au-NPs of medium size could be recovered and reused several times without loss of activity, and they showed good activity and selectivity in amide formation from alcohols and amines. Superior activity and selectivity of gold nanoparticles (Au-NPs) of medium size (4.5-11 nm) were found for the direct and selective aerobic oxidative amide synthesis from various combinations of aldehydes and amines. This is an example of an unusual correlation between the size of NPs and their activity/selectivity. These catalysts could be recovered and reused several times without loss of activity.
- Miyamura, Hiroyuki,Min, Hyemin,Soulé, Jean-Fran?ois,Kobayashi, Shu
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supporting information
p. 7564 - 7567
(2015/06/25)
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- Preparation of polymer incarcerated gold nanocluster catalysts (PI-Au) and their application to aerobic oxidation reactions of boronic acids, alcohols, and silyl enol ethers
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Heterogeneous gold nanocluster catalysts immobilized by the method known as polymer incarceration were prepared. Polystyrene-derived polymers with epoxide and alcohol moieties, which could be cross-linked under heating conditions, were employed as supports for their preparation. Cationic gold salts were reduced in a solution of NaBH4 and the polymers. Poor solvents for the polymers were added, and the polymers were precipitated and encapsulated gold nanoclusters with weak but multiple interactions between a gold nanocluster surface and the π electrons of benzene rings. The polymer capsules were heated under neat conditions to afford heterogeneous gold nanocluster catalysts; namely, polymer-incarcerated gold nanoclusters. The catalysts thus prepared could be applied to the aerobic oxidation of phenyl boronic acids, alcohols, and silyl enol ethers. We found that the choice of polymers, good and poor solvents for the polymers, metal loadings, heating conditions for cross-linking, and final activation were all crucial for obtaining high-activity catalysts.
- Miyamura, Hiroyuki,Yasukawa, Tomohiro,Kobayashi, Shu
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p. 6039 - 6049
(2015/03/30)
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- Selective imine formation from alcohols and amines catalyzed by polymer incarcerated gold/palladium alloy nanoparticles with molecular oxygen as an oxidant
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Carbon black stabilized, polymer incarcerated gold/palladium alloy nanoparticles (PICB-Au/Pd) act as an efficient, reusable heterogeneous catalyst for imine synthesis from alcohols and amines through a tandem oxidative process using molecular oxygen as the terminal oxidant.
- Soule, Jean-Francois,Miyamura, Hiroyuki,Kobayashi, Shu
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supporting information
p. 355 - 357
(2013/02/23)
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- Copolymer-incarcerated nickel nanoparticles with N-heterocyclic carbene precursors as active cross-linking agents for Corriu-Kumada-Tamao reaction
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We have developed heterogeneous polymer-incarcerated nickel nanoparticles (NPs), which catalyze cross-coupling reactions. The matrix structure of these catalysts incorporates both N-heterocyclic carbenes (NHCs) as ligands and Ni-NPs, thanks to a new design of cross-linking agents in polymer supports. These embedded NHCs were detected by field gradient swollen-resin magic angle spinning NMR analysis. They were successfully applied to Corriu-Kumada-Tamao reactions with a broad substrate scope including functional group tolerance, and the catalyst could be recovered and reused several times without loss of activity.
- Soule, Jean-Francois,Miyamura, Hiroyuki,Kobayashi, Shu
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supporting information
p. 10602 - 10605
(2013/08/23)
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- Direct amidation from alcohols and amines through a tandem oxidation process catalyzed by heterogeneous-polymer-incarcerated gold nanoparticles under aerobic conditions
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We describe herein a highly elegant and suitable synthesis of amide products from alcohols and amines through a tandem oxidation process that uses molecular oxygen as a terminal oxidant. Carbon-black-stabilized polymer-incarcerated gold (PICB-Au) or gold/cobalt (PICB-Au/Co) nanoparticles were employed as an efficient heterogeneous catalyst depending on alcohol reactivity and generated only water as the major co-product of the reaction. A wide scope of substrate applicability was shown with 42 examples. The catalysts could be recovered and reused without loss of activity by using a simple operation. Gold standard: A highly efficient green method for amide synthesis from alcohols and amines catalyzed by gold nanoparticles stabilized by styrene-based copolymers has been developed (see scheme). Two catalysts have been used with high selectivity depending on the combination of substrates. These Au nanoparticle catalysts can be recovered and reused several times by simple operations. Copyright
- Soule, Jean-Francois,Miyamura, Hiroyuki,Kobayashi, Shu
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supporting information
p. 2614 - 2626
(2013/11/19)
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- α-Hydroxylation of 1,3-dicarbonyl compounds catalyzed by polymer-incarcerated gold nanoclusters with molecular oxygen
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α-Hydroxylation of 1,3-dicarbonyl compounds was successfully catalyzed by carbon-stabilized polymer-incarcerated gold nanoclusters (PI/CB-Au). The reaction proceeded under mild conditions using molecular oxygen as oxidant with wide substrate scopes and the catalyst could be recovered and reused by a simple operation. The control experiments and the reaction monitoring revealed that α-peroxide compounds were reaction intermediates, and PI/CB-Au also catalyzed isomerization.
- Miyamura, Hiroyuki,Kobayashi, Shu
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supporting information
p. 976 - 978
(2012/10/30)
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- Polymer-incarcerated chiral Rh/Ag nanoparticles for asymmetric 1,4-addition reactions of arylboronic acids to enones: Remarkable effects of bimetallic structure on activity and metal leaching
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Robust and highly active bimetallic Rh nanoparticle (NP) catalysts, PI/CB Rh/Ag, have been developed and applied to the asymmetric 1,4-addition of arylboronic acids to enones without leaching of the metals. We found that the structures of the bimetallic Rh/Ag catalysts and chiral ligands strongly affect their catalytic activity and the amount of metal leaching. PI/CB Rh/Ag could be recycled several times by simple operations while keeping high yields and excellent enantioselectivities. To show the versatility of the PI/CB Rh/Ag catalyst, a one-pot, oxidation-asymmetric 1,4-addition reaction of an allyl alcohol and an arylboronic acid was demonstrated by combining the PI/CB Rh/Ag catalyst with PI/CB Au as an aerobic oxidation catalyst.
- Yasukawa, Tomohiro,Miyamura, Hiroyuki,Kobayashi, Shu
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supporting information
p. 16963 - 16966
(2013/01/15)
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- Rate-acceleration in gold-nanocluster-catalyzed aerobic oxidative esterification using 1,2- and 1,3-diols and their derivatives
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Aerobic oxidation of aldehydes to 1,2- and 1,3-diol monoesters was catalyzed by polymer-incarcerated gold nanoclusters under ambient conditions. The esterification proceeded much faster with 1,2- and 1,3-diols and their derivatives rather than with methanol. Magnum PI: Gold-nanocluster catalysts, PI-Au, that were immobilized on polystyrene-based polymers with cross-linking moieties, were used to catalyze the syntheses of 1,2 and 1,3-diol monoesters and their derivatives from aldehydes. The effect of neighboring-group participation in the esterification reaction is also described. Copyright
- Yasukawa, Tomohiro,Miyamura, Hiroyuki,Kobayashi, Shu
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supporting information; experimental part
p. 621 - 627
(2011/10/12)
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- Powerful amide synthesis from alcohols and amines under aerobic conditions catalyzed by gold or gold/iron, -nickel or-cobalt nanoparticles
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Considering the importance of the development of powerful green catalysts and the omnipresence of amide bonds in natural and synthetic compounds, we report here on reactions between alcohols and amines for amide bond formation in which heterogeneous gold and gold/iron, -nickel, or-cobalt nanoparticles are used as catalysts and molecular oxygen is used as terminal oxidant. Two catalysts show excellent activity and selectivity, depending on the type of alcohols used. A wide variety of alcohols and amines, including aqueous ammonia and amino acids, can be used for the amide synthesis. Furthermore, the catalysts can be recovered and reused several times without loss of activity.
- Soule, Jean-Francois,Miyamura, Hiroyuki,Kobayashi, Shu
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experimental part
p. 18550 - 18553
(2012/01/06)
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- Remarkable effect of bimetallic nanocluster catalysts for aerobic oxidation of alcohols: Combining metals changes the activities and the reaction pathways to aldehydes/carboxylic acids or esters
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Selective oxidation of alcohols catalyzed by novel carbon-stabilized polymer-incarcerated bimetallic nanocluster catalysts using molecular oxygen has been developed. The reactivity and the selectivity were strongly dependent on the combination of metals and solvent systems; aldehydes and ketones were obtained by the gold/platinum catalyst in benzotrifluoride, and esters were formed by the gold/palladium catalyst in methanol. To the best of our knowledge, this is the first example that the reaction pathway has been changed dramatically in gold catalysis by combining with a second metal. The differences in the activity and the selectivity are considered to be derived from the difference in the structure of the bimetallic clusters.
- Kaizuka, Kosuke,Miyamura, Hiroyuki,Kobayashi, Shu
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supporting information; experimental part
p. 15096 - 15098
(2011/01/08)
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- Aerobic oxidative esterification of alcohols catalyzed by polymer-incarcerated gold nanoclusters under ambient conditions
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Environmentally benign aerobic oxidation of alcohols to methyl esters catalyzed by polymer-incarcerated gold nanoclusters (PI-Au) was developed and reactions proceeded under very mild conditions. The catalyst could be recovered by simple operations without significant loss of activity.
- Miyamura, Hiroyuki,Yasukawa, Tomohiro,Kobayashi, Sh
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supporting information; experimental part
p. 776 - 778
(2010/09/05)
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- Comparison of the catalytic activity of gold nanoparticles supported in ceria and incarcerated in styrene copolymer
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The catalytic activity of gold nanoparticles supported on nanoparticulated ceria or incarcerated in a styrene copolymer has been compared for three general gold catalyzed reactions, namely the aerobic benzylamine and aniline oxidations and for phenylacetylene-aminebenzaldehyde coupling. Remarkable differences between the activity of both catalysts were observed.
- Perez, Yolanda,Aprile, Carmela,Corma, Avelino,Garcia, Hermenegildo
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experimental part
p. 204 - 209
(2011/01/03)
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- PALLADIUM CATALYST COMPOSITION
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The present invention discloses 1) a catalyst composition consisting of a crosslinked organic polymer compound and a palladium catalyst, wherein said catalyst is physically carried on said crosslinked organic polymer compound, 2) a manufacturing method of the above catalyst composition 1), characterized by homogenizing a straight chain organic polymer compound, having a crosslinkable functional group, and a palladium catalyst in a solvent dissolving said straight chain organic polymer compound, then depositing a composition thus formed and subjecting the crosslinkable functional group in said deposit to a crosslinking reaction, 3) a method for substitution reaction at an allyl position, characterized by reacting an allyl carbonate and a neucleophilic agent in the presence of the above catalyst composition 1), and 4) a method for oxidizing an alcohol, characterized by subjecting the above catalyst composition 1) to reaction with an alcohol. The catalyst composition of the present invention can be safely and easily handled without danger of spontaneous ignition, and the like, and is extremely useful as a catalyst for various chemical reactions, and further activity thereof is not decreased by repeated use thereof and a metal catalyst does not leak from a polymer compound which is a carrier thereof.
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