title: Highly Stereoselective Synthesis of Conjugated Polyenes via a Homocoupling Reaction of Unsaturated Silanes.
abstract: 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 PdCl(2) in methanol and in the presence of LiCl and CuCl(2). 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.
authors.affiliation: Centro CNR di Studio sulle Metodologie Innovative di Sintesi Organiche, Dipartimento di Chimica, Università di Bari, via Amendola 173, 70126 Bari, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Babudri
authors.forename: Angela R.
authors.initials: AR
authors.lastname: Cicciomessere
authors.forename: Gianluca M.
authors.initials: GM
authors.lastname: Farinola
authors.forename: Vito
authors.initials: V
authors.lastname: Fiandanese
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Marchese
authors.forename: Roberta
authors.initials: R
authors.lastname: Musio
authors.forename: Francesco
authors.initials: F
authors.lastname: Naso
authors.forename: Oronzo
authors.initials: O
authors.lastname: Sciacovelli