41790-87-8Relevant academic research and scientific papers
Microwave-assisted palladium-catalyzed highly regio- and stereoselective head to head dimerization of terminal aryl alkynes in water
Buxaderas, Eduardo,Alonso, Diego A.,Njera, Carmen
, p. 46508 - 46512 (2014)
A highly regio- and stereoselective oxime palladacycle/imidazolinium-catalyzed head to head dimerization of terminal aryl alkynes in water is presented. The reaction, which is carried out at 130 °C under microwave irradiation in the presence of 1,3-bis-(2,6-diisopropylphenyl)imidazolinium chloride as ligand, triethylamine as base, and TBAB as surfactant, allows the synthesis of (E)-1,4-enynes as single stereoisomers in good isolated yields.
Stereo- A nd regioselective dimerization of alkynes to enynes by bimetallic syn-carbopalladation
Pfeffer, Camilla,Wannenmacher, Nick,Frey, Wolfgang,Peters, René
, p. 5496 - 5505 (2021/05/31)
Enynes are important motifs in bioactive compounds. They can be synthesized by alkynea'alkyne couplings for which a number of mechanisms have been suggested depending on catalyst type and dominant product isomers. Regarding bimetallic pathways, hydrometalations and anti-carbopalladations have been discussed to account for the formation of geminally substituted and (Z)-configured enynes, respectively. Here we report a bimetallic alkynea'alkyne coupling that yields (E)-configured enynes. An unusual type of acetylide Pd bridging was found in putative catalytic intermediates which is arguably responsible for the regio- A nd stereochemical reaction outcome. Mechanistic studies suggest that a double μa'κ:η2 acetylide bridging enables a bimetallic syn-carbometalation. Interestingly, depending on the reaction conditions, it is also possible to form the geminal regioisomer as major product with the same catalyst. This regiodivergent outcome is explained by bi-versus monometallic reaction pathways.
Coordination chemistry of H-spirophosphorane ligands towards pentacarbonylchlororhenium(I) – synthesis, structure and catalytic activity of complexes
Skar?yńska, Anna,Siczek, Mi?osz,Gawryszewska, Paula,Chaczko, Karolina
, (2020/05/22)
Synthesis of a group of carbonyl rhenium coordination compounds with hydrospirophosphorane ligands was carried out and described. Different symmetrical HP(OCH2CH2NH)2L1, HP(OCH2CMe2NH)2L2,
Selective dimerization of terminal acetylenes in the presence of PEPPSI precatalysts and relative chloro- and hydroxo-bridged N-heterocyclic carbene palladium dimers
Ostrowska, Sylwia,Szymaszek, Natalia,Pietraszuk, Cezary
, p. 63 - 69 (2018/01/17)
Highly regio- and stereoselective dimerization of terminal acetylenes occurs in the presence of [PdCl2(IPr)(3-chloropyridine)], other members of the family of PEPPSI precatalysts and the structurally related N-heterocyclic carbene palladium dim
Platinum Complexes Bearing Bulky N-Heterocyclic Carbene Ligands as Efficient Catalysts for the Fully Selective Dimerization of Terminal Alkynes
?ak, Patrycja,Bo?t, Ma?gorzata,Lorkowski, Jan,Kubicki, Maciej,Pietraszuk, Cezary
, p. 3627 - 3631 (2017/09/06)
New platinum(0) complexes of the general formula [(NHC)Pt(dvtms)] (dvtms=1,3-divinyltetramethyldisiloxane) containing bulky N-heterocyclic carbene (NHC) ligands were prepared, characterized, and found to be catalytically active in the fully regio- and ste
Regio- and stereoselective dimerization of arylacetylenes and optical and electrochemical studies of (E)-1,3-enynes
Morozov, Oleg S.,Asachenko, Andrey F.,Antonov, Denis V.,Kochurov, Vitaly S.,Paraschuk, Dmitry Yu.,Nechaev, Mikhail S.
, p. 2671 - 2678 (2014/09/29)
The N-heterocyclic carbene palladium complex (SIPr)Pd(cinnamyl)Cl [SIPr=N,N'-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene) promotes regio- and stereospecific dimerization of a variety of arylalkynes to give (E)-1,3-enynes in good to excellent yields. An efficient and practical procedure for their synthesis was developed using a biphasic aqueous alkali/heptane system. Optical and electronic properties of (E)-1,3-enynes are highly tunable. Depending on the nature of the substituents, HOMO energies vary in the range 5.3-6.0eV. (E)-1,3-Enynes can exhibit intense photoluminescence in the spectral region 350-500nm.
Carboxylate switch between hydro- and carbopalladation pathways in regiodivergent dimerization of alkynes
Zatolochnaya, Olga V.,Gordeev, Evgeniy G.,Jahier, Claire,Ananikov, Valentine P.,Gevorgyan, Vladimir
supporting information, p. 9578 - 9588 (2014/08/18)
Experimental and theoretical investigation of the regiodivergent palladium-catalyzed dimerization of terminal alkynes is presented. Employment of N-heterocyclic carbene-based palladium catalyst in the presence of phosphine ligand allows for highly regio- and stereoselective head-to-head dimerization reaction. Alternatively, addition of carboxylate anion to the reaction mixture triggers selective head-to-tail coupling. Computational studies suggest that reaction proceeds via the hydropalladation pathway favoring head-to-head dimerization under neutral reaction conditions. The origin of the regioselectivity switch can be explained by the dual role of carboxylate anion. Thus, the removal of hydrogen atom by the carboxylate directs reaction from the hydropalladation to the carbopalladation pathway. Additionally, in the presence of the carboxylate anion intermediate, palladium complexes involved in the head-to-tail dimerization display higher stability compared to their analogues for the head-to-head reaction. Track changer: The regiodivergent palladium-catalyzed dimerization of terminal alkynes was studied. High regio- and stereoselectivity was achieved for both head-to-head and head-to-tail dimerization reactions. Computational studies suggest hydropalladation to favor head-to-head dimerization under neutral conditions. Addition of carboxylate anions switches the reaction from hydropalladation to carbopalladation pathway securing head-to-tail coupling (see scheme).
General and selective head-to-head dimerization of terminal alkynes proceeding via hydropalladation pathway
Jahier, Claire,Zatolochnaya, Olga V.,Zvyagintsev, Nickolay V.,Ananikov, Valentine P.,Gevorgyan, Vladimir
supporting information; experimental part, p. 2846 - 2849 (2012/07/17)
A general highly regio- and stereoselective palladium-catalyzed head-to-head dimerization reaction of terminal acetylenes is presented. This methodology allows for the efficient synthesis of a variety of 1,4-enynes as single E stereoisomers. Computational studies reveal that this dimerization reaction proceeds via the hydropalladation pathway.
One-pot desilylation/dimerization of terminal alkynes by ruthenium and acid-promoted (RAP) catalysis
Pasquini, Chiara,Bassetti, Mauro
supporting information; experimental part, p. 2405 - 2410 (2010/12/29)
The dimerization of terminal arylalkynes promoted by the (p-cymene)ruthenium dichloride dimer/acetic acid system {[RuCl 2(p-cymene)]2/AcOH} can be performed starting from the trimethylsilylethynyl derivatives (12 substrates), deprotected in situ, to afford 1,4-disubstituted 1-en-3-ynes with high regio- and (E)-stereoselectivity, at room temperature. The extension of this unprecedented two-reaction sequence to a diyne substrate affords a fluorene-based conjugated oligomer. The reaction mixture resulting from the desylilation-dimerization process dimerizes additional aliquots of phenylacetylene. The one-pot protocol results in shorter reaction times due to the presence of acetate salts which increase the concentration of active catalytic species, in which the acetate ligand acts as base toward the bound alkyne. The ruthenium source is transformed into a new trihapto-hexa-1,3-dien-5-yn-3-yl complex, formed by metal-assisted coupling of the enyne product and the terminal alkyne, and still maintaining catalytic activity. Selectivity, endurance, medium and functional group compatibility are the key features of the catalytic system obtained from the p-cymene ruthenium dimer under the one-pot conditions.
