Naslov
Photochemical Transformation of Oxygen and Nitrogen Heterostilbenes to Polycyclic Derivatives

Autori
Basarić, Nikola ; Butković, Kristina ; Škorić, Irena ; Marinić, Željko ; Šindler-Kulyk, Marija

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
XXth IUPAC Symposium on Photochemistry : Book of Abstracts / Quientero, B. ; Cabeza, M. C. - Granada, 2004, 225-225

Skup
XXth IUPAC Symposium on Photochemistry

Mjesto i datum
Granada, Španjolska, 17.07.2004. - 22.07.2004

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
photochemistry; furan; benzofuran; naphthofuran; o-divinylstilbene; pyrrole; sydnone; photocycloaddition

Sažetak
In this presentation a review of our work, published (1-5) and unpublished, on the photochemical behaviour and transformation of hexatriene system, partially inbeded in aromatic/heteroaromatic ring and subtituted or disubstituted with furan, pyrrole and sydnone, to polycyclic derivatives will be illustrated. Heterostilbenes with the extended conjugation in ortho position undergo, besides already known electrocyclization reactions and formation of condensed heteroaromatics, diverse intramolecular cycloaddition reactions and formation of heteropolycyclic compouns depending on heteroatom. The furan heteroaromatic analogues of o-vinylstilbene 1a as well as the 5-furan substituted derivatives undergo intramolecular cycloaddition and formation of benzobicyclo-[3.2.1]heptadiene structure with fused furan ring by initial [2+2] cycloaddition and formation of 1, 4-biradical followed by allylic rearrangement and ring closure. The pyrrole analogue of o-vinylstilbene 1b behaves quite different. It undergoes intermolecular addition of the pyrrole moiety at the position 5 to the double bond of the other molecule and formation of dimeric products. The vinyl-group does not participate in the reaction. The reaction proceeds via electron transfer and radical combination. We succeeded to obtain the intramolecular reaction and formation of pyrrole fused bezobicyclo-[3.2.1]heptadiene structure by irradiation of properly nitrogen substituted pyrrole derivatives. Difuran derivative 1c, depending on concentration and substitution, reacts intramolecularly giving benzobicyclo-[3.2.1]heptadiene structure or intermolecularly giving cyclophane derivative. Dipyrrole derivative 1d undergoes initial intramolecular reaction to the indane intermediate followed by nucleophilic attack of the starting compound or solvent. When the pyrrole ring is a part of hexatriene system, like in 1e, the rection proceeds intramolecularly giving indole and isoindole derivatives. In the case of sydnone derivatives 1f and 1g, respecively photochemical decarboxylation followed by intramolecular addition gives guinoline and diazacyclopentalene derivative. Reaction mechanisms based on isolated products will be discussed.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

POVEZANOST RADA