- New heterogenized gold(I)-heterocyclic carbene complexes as reusable catalysts in hydrogenation and cross-coupling reactions
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Mononuclear unsymmetrical N-heterocyclic carbene-gold complexes and the corresponding solid catalysts in which a gold-carbene complex has been immobilized on silica gel, ordered mesoporous silica (MCM-41), and delaminated zeolite (ITQ-2) have been prepared. These new catalysts have been tested in the hydrogenation of alkenes and the Suzuki cross-coupling reaction to afford selectively non-symmetrical biaryls. These reactions were studied with the soluble as well as with the heterogenized counterpart catalysts. The high accessibility introduced by the structure of the supports allows the preparation of highly efficient immobilized catalysts with TOFs up to 400 h-1. Moreover, the heterogenized complexes were reused and no deactivation of the catalysts can be observed.
- Corma,Gutierrez-Puebla,Iglesias,Monge,Perez-Ferreras,Sanchez
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- Oxo-Rhenium-Catalyzed Radical Addition of Benzylic Alcohols to Olefins
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Although carbon radicals generated from a variety of alcohol derivatives have proven valuable in coupling and addition reactions, the direct use of alcohols as synthetically useful radical sources is less known. In this report, benzylic alcohols are shown to be effective radical precursors for addition reactions to alkenes when treated with triphenylphosphine or piperidine with the catalyst ReIO2(PPh3)2 (I).
- Bandari, Chandrasekhar,Nicholas, Kenneth M.
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p. 3320 - 3327
(2020/03/23)
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- Vanadium(V)-Induced Oxidative Cross-Coupling of Various Boron and Silyl Enolates
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Intermolecular oxidative cross-coupling of two different enolates is one of the most useful reactions to synthesize unsymmetrical 1,4-dicarbonyl compounds. In this study, the oxovanadium(V)-induced intermolecular oxidative cross-coupling of enolates afforded unsymmetrical 1,4-dicarbonyl compounds. Various boron and silyl enolates underwent the formation of ketone–ester, ester–ketone, ester–ester, amide–ketone and amide–ester coupling products. These results clearly show the versatility of the present oxidative cross-coupling protocol.
- Amaya, Toru,Osafune, Yuma,Maegawa, Yusuke,Hirao, Toshikazu
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p. 1301 - 1304
(2017/06/23)
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- Enantioselective β-Protonation by a Cooperative Catalysis Strategy
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An enantioselective N-heterocyclic carbene (NHC)-catalyzed β-protonation through the orchestration of three distinct organocatalysts has been developed. This cooperative catalyst system enhances both yield and selectivity, compared to only the NHC-catalyz
- Wang, Michael H.,Cohen, Daniel T.,Schwamb, C. Benjamin,Mishra, Rama K.,Scheidt, Karl A.
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supporting information
p. 5891 - 5894
(2015/05/27)
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- First pre-functionalised polymeric aromatic framework from mononitrotetrakis(iodophenyl)methane and its applications
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Starting from mononitrotetrakis(iodophenyl)methane as monomer, we report the preparation of the first pre-functionalised porous aromatic frameworks (PAFs) and their application as supports for organometallic catalysts. Neutral coordinate imino-pyridine Schiff base (PAF-NPy) or chiral bis-amino (PAF-NPro) ligands were obtained by post-synthetic treatment of PAF-NH2 and treated with copper(I) or rhodium(I) to yield the corresponding supported transition-metal catalysts. The as-prepared PAF-NN-M catalysts exhibited activity and selectivity similar to that of the corresponding homogeneous catalysts and were easily removed from reaction media and recycled without loss of activity or selectivity. New copper catalysts: The preparation of pre-functionalised porous aromatic frameworks (PAFs) and their application as supports for organometallic catalysts (see figure) is reported for the first time.
- Verde-Sesto, Ester,Pintado-Sierra, Mercedes,Corma, Avelino,Maya, Eva M.,De La Campa, Jose G.,Iglesias, Marta,Sanchez, Felix
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supporting information
p. 5111 - 5120
(2014/05/06)
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- Rh-catalyzed asymmetric hydroformylation of functionalized 1,1-disubstituted olefins
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The first method for the highly enantioselective rhodium-catalyzed hydroformylation of 1,1-disubstituted olefins has been developed. By employing either of the P-chirogenic phosphine ligands BenzP* and QuinoxP*, linear aldehydes with β-chirality can be prepared in a highly enantioselective fashion with good chemo- and regioselectivities.
- Wang, Xiao,Buchwald, Stephen L.
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supporting information; experimental part
p. 19080 - 19083
(2012/01/05)
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- Improved palladium and nickel catalysts heterogenised on oxidic supports (Silica, MCM-41, ITQ-2, ITQ-6)
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Two series of solid catalysts in which a chiral palladium or nickel complex with Schiff bases as ligands have been immobilized on ordered mesoporous silica supports (MCM-41), delaminated ITQ-2, ITQ-6 zeolites and amorphous silica have been prepared. Hydrogenation of alkenes and imines was studied with the homogeneous as well as with the counterpart heterogenized catalysts. The high accessibility introduced by the structure of the supports allows the preparation of highly efficient immobilized catalysts with TOFs of 1,000,000 h -1. A moderate acidity in the support increases the catalytic activity considerably, and the easy recoverable immobilized catalysts can duplicate the activity of the homogeneous analogues. No deactivation of the catalysts was observed after repeated recycling.
- Gonzalez-Arellano,Corma,Iglesias,Sanchez
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p. 1316 - 1328
(2007/10/03)
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- Therapeutic substituted indole compounds and compositions thereof
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The present invention is concerned with compounds of formula (I) STR1 wherein R, R1 and R2 are independently selected from hydrogen and C1-4 alkyl; R3 and R4 are independently selected from hydrogen, C1-6 alkyl (including cycloalkyl) and aryl (wherein the alkyl or aryl group, which latter includes benzyl, is optionally substituted by one or more atoms or groups independently selected from halogen, C1-4 alkyl and aryl), provided R3 benzyl or substituted benzyl when R4 =H; m is an integer of from 0 to 2; n is an integer of from 0 to 3; (W) is a group of formula (i), (ii), (iii), or (iv) STR2 wherein Y is selected from oxygen, methylene and >N--R5, where R5 is hydrogen, C1-4 alkyl, or benzyl, Z and Z' are independently selected from >C=O, >C=S and methylene, and the chiral center * in formula (i) or (ii) is in its (S) or (R) form or is a mixture thereof in any proportions; X is a group selected from aryl (including heteroaryl) xanthenyl dibenzofuranyl which group is optionally substituted; and salts and solvates thereof, the preparation of these compounds, pharmaceutical formulations containing them and their use in medicine, particularly in the treatment of migraine.
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