1652-96-6Relevant academic research and scientific papers
OXIDATION OF OLEFINS BY OXYGEN WITH A MIXED PALLADIUM/SILVER NITRITE CATALYST IN ALCOHOLS.
Sage, Jean-Marc,Gore, Jacques,Guilmet, Elisabeth
, p. 6319 - 6322 (1989)
Selective oxidation of a terminal olefin by a mixed catalytic system comprising Pd(dba)2 and silver nitrite gives a methyl ketone.A WACKER type mechanism is proposed, in which organic nitrites derives from the alcoholic solvent used are involved.
Selective Alkyne Semi-Hydrogenation by PdCu Nanoparticles Immobilized on Stereocomplexed Poly(lactic acid)
Capozzoli, Laura,Evangelisti, Claudio,Frediani, Marco,Mohammadi Dehcheshmeh, Iman,Najafi Moghadam, Peyman,Oberhauser, Werner,Poggini, Lorenzo
, (2022/03/01)
Polymer-supported PdCu alloy nanoparticles with a palladium to copper atom ratio of 1 have been synthesized upon: (i) Coordination of palladium/copper acetate to 2,2’-bipyridine-end functionalized poly(lactic acid) (PLA); (ii) Stereocomplexation of PLA-based macrocomplexes of opposite stereochemistry, and (iii) metal reduction with hydrogen. The obtained supported PdCu nanoparticles were successfully applied in the semi-hydrogenation of industrially important alkynols, such as 3-hexyn-1-ol and 2-butyne-1,4-diol leading to the corresponding cis-alkenol in high selectivity (98 %) under mild reaction conditions (i. e. ethanol, T (25 °C), p(H2)=3 bar) in the absence of any further additive. From a comparison of the catalytic performance of supported PdCu nanoparticles with those of Pd and Cu, located in the same chemical environment, emerged a clear alloy effect (i. e. high chemoselectivity for the alkene at high alkyne conversion). Recycling experiments conducted with the PdCu-based catalyst proved the stability of the catalyst with time, even by its recovering in air atmosphere.
Mild olefin formationviabio-inspired vitamin B12photocatalysis
Bam, Radha,Pollatos, Alexandros S.,Moser, Austin J.,West, Julian G.
, p. 1736 - 1744 (2021/02/22)
Dehydrohalogenation, or elimination of hydrogen-halide equivalents, remains one of the simplest methods for the installation of the biologically-important olefin functionality. However, this transformation often requires harsh, strongly-basic conditions, rare noble metals, or both, limiting its applicability in the synthesis of complex molecules. Nature has pursued a complementary approach in the novel vitamin B12-dependent photoreceptor CarH, where photolysis of a cobalt-carbon bond leads to selective olefin formation under mild, physiologically-relevant conditions. Herein we report a light-driven B12-based catalytic system that leverages this reactivity to convert alkyl electrophiles to olefins under incredibly mild conditions using only earth abundant elements. Further, this process exhibits a high level of regioselectivity, producing terminal olefins in moderate to excellent yield and exceptional selectivity. Finally, we are able to access a hitherto-unknown transformation, remote elimination, using two cobalt catalysts in tandem to produce subterminal olefins with excellent regioselectivity. Together, we show vitamin B12to be a powerful platform for developing mild olefin-forming reactions.
Cobalt-Catalyzed Intermolecular Hydrofunctionalization of Alkenes: Evidence for a Bimetallic Pathway
Zhou, Xiao-Le,Yang, Fan,Sun, Han-Li,Yin, Yun-Nian,Ye, Wei-Ting,Zhu, Rong
supporting information, p. 7250 - 7255 (2019/05/16)
A functional group tolerant cobalt-catalyzed method for the intermolecular hydrofunctionalization of alkenes with oxygen- and nitrogen-based nucleophiles is reported. This protocol features a strategic use of hypervalent iodine(III) reagents that enables a mechanistic shift from conventional cobalt-hydride catalysis. Key evidence was found supporting a unique bimetallic-mediated rate-limiting step involving two distinct cobalt(III) species, from which a new carbon-heteroatom bond is formed.
Mechanistic Insight into Synergistic Catalysis of Olefin Hydrogenation by a Hetero-Dinuclear RuII-CoII Complex with Adjacent Reaction Sites
Hong, Dachao,Ohgomori, Yuji,Shimoyama, Yoshihiro,Kotani, Hiroaki,Ishizuka, Tomoya,Kon, Yoshihiro,Kojima, Takahiko
supporting information, p. 11284 - 11288 (2019/09/03)
We have designed and synthesized a hetero-dinuclear RuII-CoII complex with a dinucleating ligand inspired by hetero-dinuclear active sites of metalloenzymes. A synergistic effect between the adjacent RuII and CoII sites has been confirmed in catalytic olefin hydrogenation by the complex, exhibiting a much higher turnover number than those of mononuclear RuII or CoII complexes as the components. A RuII-hydrido species was detected by 1H NMR and electrospray ionization (ESI)-time-of-flight (TOF)-MS measurements as an intermediate to react with olefins, and CoII-bound methanol was suggested to act as a proton source.
Prominent hydrogenation catalysis of a PVP-stabilized Au34 superatom provided by doping a single Rh atom
Hasegawa, Shingo,Takano, Shinjiro,Yamazoe, Seiji,Tsukuda, Tatsuya
supporting information, p. 5915 - 5918 (2018/06/13)
A single rhodium atom was precisely doped into a gold cluster Au34 stabilized by poly(N-vinyl-2-pyrrolidone) (Au:PVP) as revealed by mass spectrometry. The Rh-atom-doped Au:PVP exhibited remarkable catalytic activity for hydrogenation reactions of olefins, which was much higher than that of recently reported Pd-atom-doped Au:PVP.
Alkene Metalates as Hydrogenation Catalysts
Büschelberger, Philipp,G?rtner, Dominik,Reyes-Rodriguez, Efrain,Kreyenschmidt, Friedrich,Koszinowski, Konrad,Jacobi von Wangelin, Axel,Wolf, Robert
, p. 3139 - 3151 (2017/03/13)
First-row transition-metal complexes hold great potential as catalysts for hydrogenations and related reductive reactions. Homo- and heteroleptic arene/alkene metalates(1?) (M=Co, Fe) are a structurally distinct catalyst class with good activities in hydrogenations of alkenes and alkynes. The first syntheses of the heteroleptic cobaltates [K([18]crown-6)][Co(η4-cod)(η2-styrene)2] (5) and [K([18]crown-6)][Co(η4-dct)(η4-cod)] (6), and the homoleptic complex [K(thf)2][Co(η4-dct)2] (7; dct=dibenzo[a,e]cyclooctatetraene, cod=1,5-cyclooctadiene), are reported. For comparison, two cyclopentadienylferrates(1?) were synthesized according to literature procedures. The isolated and fully characterized monoanionic complexes were competent precatalysts in alkene hydrogenations under mild conditions (2 bar H2, r.t., THF). Mechanistic studies by NMR spectroscopy, ESI mass spectrometry, and poisoning experiments documented the operation of a homogeneous mechanism, which was initiated by facile redox-neutral π-ligand exchange with the substrates followed by H2 activation. The substrate scope of the investigated precatalysts was also extended to polar substrates (ketones and imines).
Palladium nanoparticles stabilised by cinchona-based alkaloids in glycerol: Efficient catalysts for surface assisted processes
Reina,Pradel,Martin,Teuma,Gómez
, p. 93205 - 93216 (2016/10/11)
Palladium nanoparticles (PdNPs) were synthesised and fully characterised, both in solution and the solid state, using naturally-occurring cinchona-based alkaloids in neat glycerol. These nano-systems were stable under reaction conditions, finding applications in hydrogenation and hydrodehalogenation processes, as a result of their surface-like behaviour. Their reactivity was improved in relation to that involving PdNPs stabilised by phosphines and also by Pd/C as a heterogenous catalyst, mainly in terms of recyclability. In particular, the colloidal palladium catalyst stabilised by quinidine was highly efficient to promote the hydrodechlorination of aromatic compounds under low dihydrogen pressure. These original catalysts found applications in the synthesis of secondary and tertiary amines including N-substituted anilines, by means of one-pot tandem Pd-catalysed methodologies under smooth conditions. In all of these processes, glycerol performed a crucial function as a liquid support for the immobilisation of nanoparticle-based catalysts, allowing both the stabilisation of the nano-catalysts and easy recycling of the catalytic phase.
Hydrocarboxylation of terminal alkenes in supercritical carbon dioxide
Estorach, Clara Tortosa,Orejon, Arantxa,Ruiz, Nuria,Masdeu-Bulto, Anna M.,Laurenczy, Gabor
experimental part, p. 3524 - 3531 (2009/02/07)
The catalytic hydrocarboxylation of linear alkenes to carboxylic acids using supercritical carbon dioxide as a solvent was studied. High selectivities in acids have been obtained. The best results were achieved when adding a perfluorinated surfactant to the reaction mixture (93% conversions and ca. 80% selectivity). Comparative multinuclear high-pressure NMR spectroscopic studies in [D8]THF and in supercritical CO2 show the formation of Pd0 species. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
Cobalt-catalyzed regioselective dehydrohalogenation of alkyl halides with dimethylphenylsilylmethylmagnesium chloride
Kobayashi, Tsuneyuki,Ohmiya, Hirohisa,Yorimitsu, Hideki,Oshima, Koichiro
supporting information; experimental part, p. 11276 - 11277 (2009/02/05)
Cobalt-catalyzed reactions of haloalkanes with dimethylphenylsilylmethylmagnesium chloride result in highly regioselective dehydrohalogenation. The reaction does not follow the conventional E2 elimination mechanism but includes β-hydride elimination from the corresponding alkylcobalt intermediate. The interesting reaction mechanism of the cobalt-catalyzed dehydrohalogenation offered unique transformations that are otherwise difficult to attain. Copyright
