排序方式: 共有79条查询结果,搜索用时 15 毫秒
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Crozet D McKay D Bijani C Gual A Godard C Claver C Maron L Urrutigoïty M Kalck P 《Dalton transactions (Cambridge, England : 2003)》2012,41(12):3369-3373
Reaction of [Rh(CO)(2){(R,R)-Ph-BPE}][BF(4)] 1 under 7 bar H(2) provides the dihydride [Rh(H)(2)(CO)(2){(R,R)-Ph-BPE}][BF(4)] 3, which reacts with the neutral hydride [Rh(H)(CO){(R,R)-Ph-BPE}] 2 arising from 3 in THF. The resulting complex is the dimeric monocationic Rh((I))-Rh((III)) complex [Rh(H)(2)(CO)(2){(R,R)-Ph-BPE}][BF(4)] 4. 相似文献
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Diego A. Lomelí-Rosales Dr. Jorge A. Delgado Dr. Miriam Díaz de los Bernardos Dr. Sara Pérez-Rodríguez Dr. Aitor Gual Prof. Carmen Claver Prof. Cyril Godard 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(35):8321-8331
A facile and straightforward methodology for the preparation of monometallic (copper and palladium) and bimetallic nanocatalysts (NiCu and PdCu) stabilized by a N-heterocyclic carbene ligand is reported. Both colloidal and supported nanoparticles (NPs) on carbon nanotubes (CNTs) were prepared in a one-pot synthesis with outstanding control on their size, morphology and composition. These catalysts were evaluated in the selective hydrogenation of alkynes and alkynols. PdCu/CNTs revealed an efficient catalytic system providing high selectivity in the hydrogenation of terminal and internal alkynes. Moreover, this catalyst was tested in the semi-hydrogenation of acetylene in industrially relevant acetylene/ethylene-rich model gas feeds and showed excellent stability even after 40 h of reaction. 相似文献
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June Izquierdo Noémie Demurget Dr. Aitor Landa Prof. Tore Brinck Prof. Jose M. Mercero Prof. Peter Dinér Prof. Mikel Oiarbide Prof. Claudio Palomo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(53):12431-12438
A bifunctional amine/squaramide catalyst promoted direct aldol addition of an hydantoin surrogate to pyridine 2-carbaldehyde N-oxides to afford adducts bearing two vicinal tertiary/quaternary carbons in high diastereo- and enantioselectivity (d.r. up to >20:1; ee up to 98 %) is reported. Acid hydrolysis of adducts followed by reduction of the N-oxide group yields enantiopure carbinol-tethered quaternary hydantoin-azaarene conjugates with densely functionalized skeletons. DFT studies of the potential energy surface (B3LYP/6–31+G(d)+CPCM (dichloromethane)) of the reaction correlate the activity of different catalysts and support an intramolecular hydrogen-bond-assisted activation of the squaramide moiety in the transition state of the catalytic reaction. 相似文献
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Dr. Greco González Miera Aitor Bermejo López Dr. Elisa Martínez-Castro Prof. Per-Ola Norrby Prof. Belén Martín-Matute 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(10):2631-2636
1,4- and 1,5-diols undergo cyclodehydration upon treatment with cationic N-heterocyclic carbene (NHC)–IrIII complexes to give tetrahydrofurans and tetrahydropyrans, respectively. The mechanism was investigated, and a metal-hydride-driven pathway was proposed for all substrates, except for very electron-rich ones. This contrasts with the well-established classical pathways that involve nucleophilic substitution. 相似文献
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Dr. Kevin Antien Dr. Aitor Lacambra Prof. Fernando P. Cossío Dr. Stéphane Massip Dr. Denis Deffieux Prof. Laurent Pouységu Dr. Philippe A. Peixoto Prof. Stéphane Quideau 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(49):11574-11580
The so-called Securinega alkaloids constitute a class of tetracyclic biologically active specialised metabolites isolated principally from subtropical plants belonging to the Phyllanthaceae family. Following a strategy based on alternative hypotheses for their biosynthesis, an easy and time-efficient divergent synthesis enabled access to twelve of those alkaloids featuring (neo)(nor)securinane skeletons. Moreover, this work permitted to reassign the absolute configurations of (+)-virosine B and (−)-episecurinol A. 相似文献
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Landa A Minkkilä A Blay G Jørgensen KA 《Chemistry (Weinheim an der Bergstrasse, Germany)》2006,12(13):3472-3483
A new, short, and simplified procedure for the synthesis of optically active pyridine derivatives from pro-chiral pyridine-N-oxides is presented. The catalytic and asymmetric Mukaiyama aldol reaction between ketene silyl acetals and 1-oxypyridine-2-carbaldehyde derivatives catalyzed by chiral copper(II)-bis(oxazoline) complexes gave optically active 2-(hydroxyalkyl)- and 2-(anti-1,2-dihydroxyalkyl)pyridine derivatives in good yields and diastereoselectivities, and in excellent enantioselectivities-up to 99 % enantiomeric excess. As a synthetic application of the developed method, a full account for the asymmetric total synthesis of a nonnatural indolizine alkaloid is provided. 相似文献
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Jiménez J Landa A Lizarraga A Maestro M Mielgo A Oiarbide M Velilla I Palomo C 《The Journal of organic chemistry》2012,77(1):747-753
The catalytic direct α-alkylation of aldehydes with 2-(bromomethyl)acrylates has been accomplished, giving rise to α-branched and functionalized aldehydes of high diastereo- and enantiopurity. The influence of the nature of the ester group of the acrylates in reaction stereoselectivity and especially in reactivity is investigated. Optimum conditions implicate the use of phenyl acrylates in conjunction with organocatalyst 8. Application of thus obtained adducts in synthesis is illustrated with a concise stereocontrolled preparation of trisubstituted cyclopentenes. 相似文献