19222-50-5Relevant articles and documents
Palladium-catalyzed cross-coupling between vinyl halides and tert-butyl carbazate: First general synthesis of the unusual N-Boc-N-alkenylhydrazines
Barluenga, Jose,Moriel, Patricia,Aznar, Fernando,Valdes, Carlos
, p. 275 - 278 (2007/10/03)
(Chemical Equation Presented) N-Boc-N-alkenylhydrazines, an almost unknown type of compounds, have been prepared with high to moderate yields via palladium-catalyzed cross-coupling between alkenyl halides and fert-butyl carbazate. The present methodology represents the first general way to access this highly functionalized and unusual type of hydrazines.
Highly Stereoselective Synthesis of Conjugated Polyenes via a Homocoupling Reaction of Unsaturated Silanes
Babudri, Francesco,Cicciomessere, Angela R.,Farinola, Gianluca M.,Fiandanese, Vito,Marchese, Guiseppe,et al.
, p. 3291 - 3298 (2007/10/03)
A new method for the synthesis of conjugated polyenes containing up to eight double bonds with all-E configuration is reported.The procedure is based upon a homocoupling reaction of dienyl-, trienyl, or tetraenylsilanes, promoted by PdCl2 in methanol and in the presence of LiCl and CuCl2.Configurational and conformational assignments were rigorously made on the basis of NMR spectra.The compounds obtained represent a novel interesting class of symmetrically substituted polyenes with potential optical and electrooptical properties.By changing the solvent, the homocoupling process can be switched to the halogenation of the silyl-substituted terminal double bond, thus leading to polyenyl halides.
Pulse Radiolysis Study of Ion Pairing of Diphenylpolyene Radical Anions with Tetrabutylammonium and Sodium Cations in Tetrahydrofuran
Aoyama, Takahisa,Yamamoto, Yukio,Hayashi, Koichiro
, p. 3353 - 3358 (2007/10/02)
Pulse radiolysis of tetrahydrofuran (THF) solutions of all-trans α,ω-diphenyl-substituted polyenes, such as 1,4-diphenylbuta-1,3-diene, 1,6-diphenylhexa-1,3,5-triene and 1,8-diphenylocta-1,3,5,7-tetraene, has been undertaken in the absence and presence of Bu4NPF6 and NaBPh4.In the presence of the salts, the absorption maxima of the diphenylpolyene radical anions are shifted to shorter wavelengths by ion pairing with Bu4N+ and Na+ as well as that of the trans-stilbene radical anion previously investigated.When Ph(CH=CH)nPH.- (n=1-4) is paired with Bu4N+, the magnitude of the spectroscopic shift is larger for n=2-4 than for n=1.On the other hand, the magnitude of the spectroscopic shift due to the ion pairing with Na+ decreases with increasing n and becomes very small in the case of n=3 or 4.The decay of the radical anions, which is due to neutralization reactions with THF(H+), is retarded by the addition of the salts.The retarding effect of the salts is attributed to the ion pairing of the reactant ions with the counterions derived from the salts.In acetonitrile solution the absorption spectra and the decay rates of the radical anions are not affected by the addition of the salts, demonstrating that the ion pairing is not important in such a polar solvent.Results for the radical anions of pyrene, perylene and triphenylethylene are presented for the sake of comparison.The appreciable spectroscopic shift due to the ion pairing with the large Bu4N+ ion was found to be characteristic of the diphenylpolyene radical anions.
