نتایج جستجو برای: ullmann reaction

تعداد نتایج: 412658  

Journal: :Organic & biomolecular chemistry 2012
Wei Zhou Wei Chen Lei Wang

2-Cyanobenzofurans and 2-cyanobenzothiophenes were prepared through an efficient one-pot Ullmann-reaction/cyanation reaction. In the presence of CuI/Na(2)CO(3)-Pd(OAc)(2)/PPh(3) in DMF, the reaction of 2-(gem-dibromovinyl)phenols and 2-(gem-dibromovinyl)thiophenols with K(4)Fe(CN)(6), as non-toxic and user-friendly cyanating reagent, proceeded smoothly to generate the corresponding 2-cyanobenzo...

A highly efficient Ullmann homocoupling reaction of aryl halides using palladium (II) phosphine-ylide complexes as homogenous pre-catalysts under aerobic conditions has been developed without the need for any chemical co‐reducing agents. The procedure is relatively mild and appears to have broad applicability, being useful for the homocoupling of both electron-deficient and electron-rich aryl h...

2017
L. Dong S. Wang W. Wang C. Chen T. Lin J. Adisoejoso

In this chapter, we report on our recent studies of on-surface Ullmann coupling reaction and focus on the roles of the transition metals in the reaction. First, we discuss an organometallic intermediate state, which separates the reaction into two steps. Next, we examine the catalytic efficiency of Cu, Au, Ag, Pt, and Pd in the reaction. We analyze the bond formation yields when the reaction ta...

Journal: :Physical chemistry chemical physics : PCCP 2015
Colin J Murphy Zachary C Smith Alex Pronschinski Emily A Lewis Melissa L Liriano Chloe Wong Christopher J Ivimey Mitchell Duffy Wojciech Musial Andrew J Therrien Samuel W Thomas E Charles H Sykes

Surface-bound molecular rotation can occur with the rotational axis either perpendicular (azimuthal) or parallel (altitudinal) to the surface. The majority of molecular rotor studies involve azimuthal rotors, whereas very few altitudinal rotors have been reported. In this work, altitudinal rotors are formed by means of coupling aryl halides through a surface-mediated Ullmann coupling reaction, ...

Journal: :Dalton transactions 2009
Andrea Biffis Cristina Tubaro Elena Scattolin Marino Basato Grazia Papini Carlo Santini Eleuterio Alvarez Salvador Conejero

Novel synthetic routes for the preparation of trinuclear copper(I) complexes with triscarbene ligands are presented, which yield higher purity products than the one previously described. The first crystal structure of one of these complexes is reported and confirms the expected structure. The trinuclear complexes proved to be efficient catalysts of Ullmann-type reactions as well as of the Sonog...

Journal: :Chemical communications 2012
Alla Pogoreltsev Ephrath Solel Doron Pappo Ehud Keinan

The Cu(I)-catalyzed Ullmann condensation reaction between aliphatic alcohols and sym-pentachlorocorannulene provides a convenient entry to 1,3,5,7,9-pentaalkoxycorannulenes. The latter are easily converted to novel deca-heterosubstituted derivatives, such as 1,3,5,7,9-penta-X-2,4,6,8,10-penta-Y-corannulenes by electrophilic aromatic substitution.

Journal: :Chemical communications 2015
Chi Zhang Qiang Sun Hua Chen Qinggang Tan Wei Xu

From an interplay of UHV-STM imaging and DFT calculations, we have illustrated on-surface formation of polyphenyl chains through a hierarchical reaction pathway involving two different kinds of reactions (Ullmann coupling and cross-dehydrogenative coupling), which will provide a deeper understanding of on-surface chemical reactions and an alternative and efficient strategy to fabricate desired ...

Journal: :Physical chemistry chemical physics : PCCP 2016
Qiang Sun Liangliang Cai Yuanqi Ding Honghong Ma Chunxue Yuan Wei Xu

Wurtz reactions feature the dehalogenated coupling of alkyl halides. In comparison to their widely investigated counterparts, Ullmann reactions, Wurtz reactions have however been scarcely explored on surfaces. Herein, by combining high-resolution STM imaging and DFT calculations, we have systematically investigated Wurtz reactions on three chemically different metal surfaces including Cu(110), ...

2016
Dimas G. de Oteyza Aran García-Lekue Manuel Vilas-Varela Néstor Merino-Díez Eduard Carbonell-Sanromà Martina Corso Guillaume Vasseur Celia Rogero Enrique Guitián Jose Ignacio Pascual J. Enrique Ortega Yutaka Wakayama Diego Peña

Contributing to the need for new graphene nanoribbon (GNR) structures that can be synthesized with atomic precision, we have designed a reactant that renders chiral (3,1)-GNRs after a multistep reaction including Ullmann coupling and cyclodehydrogenation. The nanoribbon synthesis has been successfully proven on different coinage metals, and the formation process, together with the fingerprints ...

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