118493-18-8Relevant 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)
(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.
Stereoselective synthesis of substituted all-trans 1,3,5,7-octatetraenes by a modified Ramberg-B?cklund reaction
Cao, Xiao-Ping
, p. 1301 - 1307 (2007/10/03)
The reaction of allylic dienylic sulfone with dibromodifiuoromethane in the presence of alumina-supported KOH in dichloromethane solution results in facile rearrangement affording the corresponding all-trans 1,3,5,7-octatetraenes in excellent yields. This result shows that the double bonds of stereochemically defined allylic dienylic sulfone retain their stereochemistry and the newly formed double bond has an (E)-configurafion in the modified Rambeig-B?cklund procedure.
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.
A HIGHLY STEREOSELECTIVE SYNTHESIS OF SUBSTITUTED BUTADIENES AND CONJUGATED POLYENES
Patro, Balaram,Ila, Hiriyakkanavar,Junjappa, Hiriyakkanavar
, p. 809 - 812 (2007/10/02)
A highly stereoselective synthesis of 1,3-butadienes and its higher enyl analogs has been developed through thermal dehydrative ring opening of cyclopropyl carbinols in dimethylsulphoxide.
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.
Palladium-Catalyzed Syntheses of Conjugated Trienes
Kasahara, Akira,Izumi, Taeko,Kudou, Naoto
, p. 704 - 705 (2007/10/02)
Conjugated trienes 3 and 5 have been prepared by the palladium-catalyzed reaction of alkenes 2 with fumaryl chloride (1) and (E)-5-phenyl-2,4-pentadienoyl chloride (4), respectively, in the presence of N-ethylmorpholine.
Preparation and Properties of endo,endo-7,8-Diphenylbicycloocta-2,4-diene
Chasey, Kent L.,Paquette, Leo A.,Blount, John F.
, p. 5262 - 5270 (2007/10/02)
endo,endo-7,8-Diphenylbicycloocta-2,4-diene (10) has been prepared in ten steps from ε-truxillic acid.If the pendant phenyl substituents in this hydrocarbon could adopt conformations where they become approximately coplanar with the diene segment, the possibility for substantive electronic delocalization through the cyclobutane relay orbitals exists.Three-dimensional X-ray crystal structure analysis of 10 reveals that while the unsaturated four-carbon bridge is essentially planar, one of the aryl rings is twisted 20 deg out of plane because proximity factors prohibit parallel stacking.Additionally, photoelectron spectroscopic analysis of 10 and several model compounds (17, 18, and 23) shed no light on the question of through-bond interaction because of high-level interference arising from electron promotion out of the benzene rings.Nonetheless, the chemical reactivity of 10 is very high, it being very prone to thermolysis and photolysis.Interestingly, the reactions which occur under these conditions find no parallel with the behavior of lesser substituted prototype structures.
