136612-96-9Relevant academic research and scientific papers
Cyclotrimerization of alkynes vs. ketone formation in aqueous microemulsion
Nairoukh, Zackaria,Fanun, Monzer,Schwarze, Michael,Schom?cker, Reinhard,Blum, Jochanan
, p. 93 - 98 (2014/01/06)
In the course of our attempts to develop sustainable conditions for the catalytic organic reactions by replacement of the traditional but environmentally disfavored organic solvents by water, we studied the cyclotrimerizations of alkynes, in aqueous microemulsions. The catalyst for these reactions was the rhodium-trichloride encaged within silica sol-gel. In acidic aqueous media, alkynes can undergo addition of water to form their corresponding ketones. In order to eliminate completely the formation of ketones, relatively low reaction temperatures are required. At higher reaction temperatures, however, buffered microemulsion media is preferable. Cyclotrimerization of alkynes proved to be dependent on the reaction temperatures, the electronic nature of the substrates, the electronic nature of the surfactant and on the hydrophobicity of the sol-gel support. During the cyclotrimerization reaction, the rhodium complex was turned to Rh(0) nanoparticles characterized by TEM measurements. These investigations may be regarded as model studies for the conversion of alkynes into substituted benzenes in water.
A ruthenium-based catalytic system with switchable selectivity between cyclotrimerization and enyne metathesis/Diels-Alder reactions of terminal alkynes
Karabulut, Solmaz,Sariaslan, Begüm,?ztürk, Bengi ?zgün
, p. 12 - 16 (2013/08/23)
In this study, we report a practical catalytic system, [RuCl 2(p-cymene)]2/IPr (IPr: 1,3-bis(2,6 diisopropylphenyl) imidazol-2-ylidene), that can switch between cyclotrimerization and cross enyne metathesis. The cyclotrimerization reaction of phenylacetylene catalyzed by [RuCl2(p-cymene)]2 can be switched to enyne metathesis by the introduction of a sterically hindered N-heterocyclic carbene. The 1,3-diene formed during this reaction reacts with dienophiles to form the Diels-Alder adduct. A practical one-pot synthesis method, utilizing enyne metathesis/Diels-Alder reactions, was used to construct cyclic compounds in an efficient manner.
Palladium-catalyzed acylation and/or homo-coupling of aryl- and alkyl-acetylenes
Perrone, Serena,Bona, Fabio,Troisi, Luigino
experimental part, p. 7386 - 7391 (2011/10/09)
Allyl or benzyl halides, through a Pd(0)-catalyzed reaction and under CO pressure, generate acyl-palladium/halides that, in the presence of a base and an aryl- and alkyl-acetylene, undergo nucleophilic acyl substitution giving conjugated acetylenic ketones. Diynes, resulting from alkyne/alkyne homo-coupling, were instead the main products in reactions performed without allyl or benzyl halides. Moreover, dimerization, trimerization, and cyclotrimerization reactions of acetylenes were observed in reaction carried out even without base.
The highly selective formation of biaryls by the cyclization of arylethynes catalyzed by vanadyl phthalocyanine
Cicero, Daniel,Lembo, Angelo,Leoni, Alessandro,Tagliatesta, Pietro
experimental part, p. 2162 - 2165 (2009/12/25)
The dimerization of arylethynes catalyzed by vanadium phthalocyanine to give substituted biaryls has been investigated. The reaction yield is always high and for many examples is only slightly affected by the aryl substituents. This fact is also related to the results obtained with metalloporphyrins, which give lower selectivities due to the presence of variable amounts of triphenylbenzenes.
