Photochemical behaviour of furylidene carbonyl compounds

✍ Scribed by Maurizio D'Auria; Andrea D'Annibale; Tommaso Ferri

• Book ID: 104203408
• Publisher: Elsevier Science
• Year: 1992
• Tongue: French
• Weight: 861 KB
• Volume: 48
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(01)85622-2

✦ Synopsis

Photophysical and electrochemical properties of furylidene carbonyl compounds were utilized in order to explain the observed photochemical behaviour.

Cinnamic acid gives photodimers when irradiated in the solid state: this reaction is stereospecific depending on the crystal form of the starting material. l-4 However, the reaction of the same substrate in solution does not give any dimerization products but only cis-trans isomerization. '16 Recently we reported a new photochemical dimerization of 3-(2-furyl)acrylic derivatives 1 to give cyclobutanes.7 This is the first example of photochemical dimerization of arylacrylic derivatives in solution in absence of Lewis acids:8V9 in fact, in our experiments we used acetonitrile as solvent in the presence of benzophenone.

Furthermore, we have reported also that furylidenetetralones 2 do not give any dimerization product, but rather the isomerization product 3." 2 3

In this paper we report our results on the mechanism of these two reactions.

Results and Discussion

Irradiation of 1 in acetonitrile in the presence of benzophenone with a 500 W high pressure mercury arc in an immersion apparatus equipped with a Pyrex filter gave a mixture of 4 (61%) and 5 (27%).