- Atom-Economical Ni-Catalyzed Diborylative Cyclization of Enynes: Preparation of Unsymmetrical Diboronates
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We report a Ni-catalyzed diborylative cyclization of enynes that affords carbo- and heterocycles containing both alkyl- and alkenylboronates. The reaction is fully atom-economical, shows a broad scope, and employs a powerful and inexpensive catalytic Ni-b
- Cabrera-Lobera, Natalia,Quirós, M. Teresa,Brennessel, William W.,Neidig, Michael L.,Bu?uel, Elena,Cárdenas, Diego J.
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p. 6552 - 6556
(2019/08/20)
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- Catalytic Generation of Rhodium Silylenoid for Alkene-Alkyne-Silylene [2 + 2 + 1] Cycloaddition
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An alkene-alkyne-silylene [2 + 2 + 1] cycloaddition takes place in the rhodium-catalyzed reaction of 1,6-enynes with borylsilanes bearing an alkoxy group on the silicon atoms, which react as synthetic equivalents of silylene. The reaction proceeds efficiently in 1,2-dichloroethane at 80-110 °C in the presence of a rhodium catalyst bearing bis(diphenylphosphino)methane (DPPM) as a ligand to afford 1-silacyclopent-2-enes in good to high yields.
- Ohmura, Toshimichi,Sasaki, Ikuo,Suginome, Michinori
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p. 1649 - 1653
(2019/03/20)
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- Iron-Catalyzed Hydroborylative Cyclization of 1,6-Enynes
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We report first Fe-catalyzed hydroborylative cyclization reaction. The process provides one C?C and one C?B bond in a single operation and shows a wide scope, allowing the formation of carbo- and heterocycles containing a homoallylic boryl unit that can b
- Cabrera-Lobera, Natalia,Rodríguez-Salamanca, Patricia,Nieto-Carmona, Juan C.,Bu?uel, Elena,Cárdenas, Diego J.
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p. 784 - 788
(2017/11/29)
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- A New Approach to Non-Coordinating Anions: Lewis Acid Enhancement of Porphyrin Metal Centers in a Zwitterionic Metal-Organic Framework
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We describe a new strategy to generate non-coordinating anions using zwitterionic metal-organic frameworks (MOFs). By assembly of anionic inorganic secondary building blocks (SBUs) ([In(CO2)4]-) with cationic metalloporphyrin-based organic linkers, we prepared zwitterionic MOFs in which the complete internal charge separation effectively prevents the potential binding of the counteranion to the cationic metal center. We demonstrate the enhanced Lewis acidity of MnIII- and FeIII-porphyrins in the zwitterionic MOFs in three representative electrocyclization reactions: [2 + 1] cycloisomerization of enynes, [3 + 2] cycloaddition of aziridines and alkenes, and [4 + 2] hetero-Diels-Alder cycloaddition of aldehydes with dienes. This work paves a new way to design functional MOFs for tunable chemical catalysis.
- Johnson, Jacob A.,Petersen, Brenna M.,Kormos, Attila,Echeverría, Elena,Chen, Yu-Sheng,Zhang, Jian
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supporting information
p. 10293 - 10298
(2016/09/03)
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- Secondary phosphine oxide-gold(I) complexes and their first application in catalysis
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A series of new secondary phosphine oxide (SPO)-gold(I) complexes have been synthesized and characterized by X-ray crystallography. Complexes exhibited dimeric structures interconnected by O-H···Cl hydrogen bonds. Their first use in homogeneous catalysis
- Schroeder, Felix,Tugny, Coralie,Salanouve, Elise,Clavier, Herve,Giordano, Laurent,Moraleda, Delphine,Gimbert, Yves,Mouries-Mansuy, Virginie,Goddard, Jean-Philippe,Fensterbank, Louis
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p. 4051 - 4056
(2014/10/15)
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- Pauson-Khand reactions in a photochemical flow microreactor
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Pauson-Khand reactions were achieved at ambient temperature without any additive using a photochemical flow microreactor. The efficiency of the reaction was better than that in a conventional batch reactor, and the reaction could be operated continuously for 1 h.
- Asano, Keisuke,Uesugi, Yuki,Yoshida, Jun-Ichi
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supporting information
p. 2398 - 2401
(2013/06/27)
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- (Pentamethylcyclopentadienyl)iridium dichloride dimer {[IrCp*Cl 2]2}: A novel efficient catalyst for the cycloisomerizations of homopropargylic diols and N-tethered enynes
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(Pentamethylcyclopentadienyl)iridium dichloride dimer {[IrCp*Cl 2]2}-catalyzed hydroalkoxylation of bis-homopropargylic alcohols provides an efficient access to dioxabicyclo[2.2.1]ketals. The cycloisomerizations proceed under mild conditions, with low catalytic loadings and short reaction times. This new protocol involving an Ir(III) catalyst also promoted the cycloisomerization of nitrogen-tethered 1,6-enynes to give azabicyclo[4.1.0]heptenes, enhancing the synthetic potential of our method. Copyright
- Benedetti, Erica,Simonneau, Antoine,Hours, Alexandra,Amouri, Hani,Penoni, Andrea,Palmisano, Giovanni,Malacria, Max,Goddard, Jean-Philippe,Fensterbank, Louis
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supporting information; experimental part
p. 1908 - 1912
(2011/10/05)
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- Iron-catalyzed, hydrogen-mediated reductive cyclization of 1,6-enynes and diynes: Evidence for bis(imino)pyridine ligand participation
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(Chemical Equation Presented) The bis(imino)pyridine iron dinitrogen complex (iPrPDI)Fe(N2)2 catalyzes the hydrogen-mediated reductive cyclization of enynes and diynes with turnover frequencies comparable to those of established precious metal catalysts. Amino, oxygenated, and carbon-based substrates are readily cyclized to the corresponding hetero- and carbocycles with 5 mol % iron and 4 atm H2 at 23°C. Stoichiometric reactions between selected substrates and the iron compound under a N2 atmosphere established transfer dehydrogenation from an isopropyl aryl substituent to either the enyne or diyne substrate. In situ monitoring of the catalytic reaction by 1H NMR spectroscopy coupled with deuterium labeling experiments established rapid cyclization followed by turnoverlimiting hydrogenation. Copyright
- Sylvester, Kevin T.,Chirik, Paul J.
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supporting information; experimental part
p. 8772 - 8774
(2009/12/04)
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- Microwave-assisted rhodium-complex-catalyzed cascade decarbonylation and asymmetric Pauson-Khand-type cyclizations
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Microwave-assisted Rh-diphosphane-complex-catalyzed dual catalysis is reported. This cooperative process provides [2+2+1] cycloadducts by sequential decarbonylation of aldehyde or formate and carbonylation of enynes within a short period of time. Various
- Hang, Wai Lee,Lai, Na Lee,Chan, Albert S. C.,Fuk, Yee Kwong
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supporting information; experimental part
p. 3403 - 3406
(2009/04/07)
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- Gold(l)-catalyzed cascade cyclization reaction: Highly regio- and diastereoselective intermodular addition of water and alcohols to epoxy alkynes
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We have developed a novel access to ketal skeletons through a highly regio- and diastereoselective intermolecular addition of water and alcohols to alkynyl epoxides catalyzed by goid(l). This procedure involves a domino three-membered ring-opening, 6-exo-
- Dai, Lun-Zhi,Qi, Ming-Juan,Shi, Yong-Ling,Liu, Xu-Guang,Shi, Min
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p. 3191 - 3194
(2008/02/11)
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- A study of (binap)(enyne)tetracarbonyldicobalt(0) complexes
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Four (binap)(enyne)tetracarbonyldicobalt(0) complexes have been synthesised and their reactivity monitored by variable temperature 31P NMR spectroscopy. Formation of (binap)dicarbonylhydridocobalt(-1) 12 occurred at temperatures between 35 and
- Gibson, Susan E.,Hardick, David J.,Haycock, Peter R.,Kaufmann, Karina A. C.,Miyazaki, Ayako,Tozer, Matthew J.,White, Andrew J. P.
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p. 7099 - 7109
(2008/03/12)
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- Salicylaldimine ruthenium alkylidene complexes: Metathesis catalysts tuned for protic solvents
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Tuning the electronic and steric environment of olefin metathesis catalysts with specialized ligands can adapt them to broader applications, including metathesis in aqueous solvents. Bidentate salicylaldimine ligands are known to stabilize ruthenium alkylidene complexes, as well as allow ringclosing metathesis in protic media. Here, we report the synthesis and characterization of exceptionally robust olefin metathesis catalysts bearing both bidentate salicylaldimine and N-heterocyclic carbene ligands, including a trimethylammonium-functionalized complex adapted for polar solvents. NMR spectroscopy and X-ray crystallographic analysis confirm the structures of the complexes. Although the N-heterocyclic carbene-salicylaldimine ligand combination limits the activity of these catalysts in non-polar solvents, this pairing enables efficient ring-closing metathesis of both dienes and enynes in methanol and methanol/water mixtures under air.
- Binder, Joseph B.,Guzei, Ilia A.,Raines, Ronald T.
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p. 395 - 404
(2008/02/07)
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- Formate as a CO surrogate for cascade processes: Rh-catalyzed cooperative decarbonylation and asymmetric Pauson-Khand-type cyclization reactions
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A rhodium-(S)-xyl-BINAP complex-catalyzed tandem formate decarbonylation and [2 + 2 + 1] carbonylative cyclization is described; this cooperative process utilizes formate as a condensed CO source, and the newly developed cascade protocol can be extended t
- Lee, Hang Wai,Chan, Albert S. C.,Kwong, Fuk Yee
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p. 2633 - 2635
(2008/02/08)
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- Rhodium-bisbenzodioxanphos complex-catalyzed homogeneous enantioselective Pauson-Khand-type cyclization in alcoholic solvents
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The chiral atropisomeric diphosphane ligand (S)-BisbenzodioxanPhos was found to be highly effective in the co-operative processeses of aldehyde decarbonylation and cascaded enantioselective Pauson-Khand-type reactions. Various 1,6-enynes were transformed
- Fuk, Yee Kwong,Hang, Wai Lee,Qiu, Liqin,Wai, Har Lam,Li, Yue-Ming,Hoi, Lun Kwong,Chan, Albert S. C.
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p. 1750 - 1754
(2007/10/03)
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- Rhodium-catalyzed asymmetric aqueous Pauson-Khand-type reaction
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An interesting rhodium-catalyzed asymmetric aqueous Pauson-Khand-type reaction was developed. A chiral atropisomeric dipyridyldiphosphane ligand was found to be highly effective in this system. This operationally simple protocol allows both catalyst and r
- Kwong, Fuk Yee,Li, Yue Ming,Lam, Wai Har,Qiu, Liqin,Lee, Hang Wai,Yeung, Chi Hung,Chan, Kin Shing,Chan, Albert S. C.
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p. 3872 - 3880
(2007/10/03)
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- Immobilized Co/Rh heterobimetallic nanoparticle-catalyzed Pauson-Khand-type reaction
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Co/Rh heterobimetallic nanoparticles were prepared from cobalt-rhodium carbonyl clusters [Co2Rh2(CO)12 and Co 3Rh(CO)12] and immobilized on charcoal. HR-TEM revealed that the size of the heterobimetal
- Kang, Hyun Park,Young, Keun Chung
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p. 854 - 866
(2007/10/03)
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