52378-67-3Relevant academic research and scientific papers
Mechanistic studies on the Pd-catalyzed vinylation of aryl halides with vinylalkoxysilanes in water: The effect of the solvent and NaOH promoter
Gordillo, Alvaro,Ortuno, Manuel A.,Lopez-Mardomingo, Carmen,Lledos, Agusti,Ujaque, Gregori,De Jesus, Ernesto
supporting information, p. 13749 - 13763 (2013/10/01)
The mechanism of the Pd-catalyzed vinylation of aryl halides with vinylalkoxysilanes in water has been studied using different catalytic precursors. The NaOH promoter converts the initial vinylalkoxysilane into a highly reactive water-soluble vinylsilanolate species. Similarly, deuterium-labeling experiments have shown that, irrespective of the catalytic precursor used, vinylation occurs exclusively at the CH vinylic functionality via a Heck reaction and not at the C-Si bond via a Hiyama cross-coupling. The involvement of a Heck mechanism is interpreted in terms of the reduced nucleophilicity of the base in water, which disfavors the transmetalation step. The Heck product (β-silylvinylarene) undergoes partial desilylation, with formation of a vinylarene, by three different routes: (a) hydrolytic desilylation by the aqueous solvent (only at high temperature); (b) transmetalation of the silyl olefin on the PdH Heck intermediate followed by reductive elimination of vinylarene; (c) reinsertion of the silyl olefin into the PdH bond of the Heck intermediate followed by β-Si syn-elimination. Both the Hiyama and Heck catalytic cycles and desilylation mechanisms b and c have been computationally evaluated for the [Pd(en)Cl2] precursor in water as solvent. The calculated Gibbs energy barriers support the reinsertion route proposed on the basis of the experimental results.
Synthesis and evaluation of a series of 1,4-diarylbutadienes for anticoccidial activity
Gage, Jennifer L.,Kirst, Herbert A.,O'Neil, Deirdre,David, Bridget A.,Smith II, Charles K.,Naylor, Sharon A.
, p. 4083 - 4091 (2007/10/03)
During the course of a collaborative screening program, a set of 1-phenyl-4-pyridyl-butadienes was found to exhibit in vitro activity against Eimeria tenella in a cell-based assay. Activity was dependent on the chain length and degree of unsaturation of t
Photoisomerization mechanisms and photoselectivity of the stereoisomers of 1-(pyrid-n-yl),4-phenylbuta-1,3-diene
Bartocci,Galiazzo,Latterini,Marri,Mazzucato,Spalletti
, p. 2911 - 2916 (2007/10/03)
The positional isomers of 1-(pyrid-n-yl),4-phenylbuta-1,3-diene (n = 2, 3 and 4) have been synthesized and characterized by spectrometric techniques. All the four expected stereoisomers (EE, EZ, ZE and ZZ) were prepared for n = 2 while only three and two geometrical isomers were obtained for the positional isomers with n = 3 and 4, respectively. Their excited state properties were investigated by stationary and pulsed fluorimetric techniques and by laser flash photolysis. This paper describes the photochemical behaviour under direct and triplet sensitized excitation. The selective formation of photoproducts and the role of diabatic/adiabatic mechanisms are reported and compared with the results on the direct photoisomerization of the EE and ZE isomers in the singlet manifold described in a previous paper (G. Bartocci, G. Galiazzo, U. Mazzucato and A. Spalletti, Phys. Chem. Chem. Phys., 2001, 3, 379-386).
Photophysics and photochemistry of the EE and ZE isomers of 1-(n-pyridyl)-4-phenyl-1,3-butadiene (n = 2, 3 and 4)
Bartocci,Galiazzo,Mazzucato,Spalletti
, p. 379 - 386 (2007/10/03)
The positional isomers of 1-(n-pyridyl)-4-phenyl-1,3-butadiene (n = 2, 3 and 4) have been synthesized in the EE and ZE geometries by common routes and characterized by spectrometric techniques. Their excited state properties were investigated by stationary and pulsed fluorimetric techniques and by laser flash photolysis. This paper reports the spectral, photophysical and photochemical behaviour of the EE and ZE isomers in a non-polar solvent. The photoisomerization proceeds through singlet, diabatic and/or adiabatic mechanisms with generally low quantum yield, owing to the role of internal conversion (markedly more important for n = 2). The role of intramolecular hydrogen bonds on the excited state properties of the ZE isomer of the 2-pyridyl derivative is particularly described.
THE ONE-POT PALLADIUM CATALYZED WITTIG REACTION WITH ALLYLIC ALCOHOLS. SCOPE AND LIMITATIONS
Moreno-Manas, M.,Ortuno, R. M.,Prat, M.,Galan, M. A.
, p. 1003 - 1014 (2007/10/02)
Some allylic alcohols react with aldehydes and triphenylphosphine in a one-pot formal Wittig reaction under Pd0 catalysis.The method has been extended to cinnamyl alcohol, 1, 2-methyl-2-propen-1-ol, 7, and 3-buten-2-ol, 11, and to heterocyclic aldehydes.
