The photo-addition of diphenylacetylene to benzo[b]thiophen

✍ Scribed by W.H.F. Sasse; P.J. Collin; D.B. Roberts

• Book ID: 104240137
• Publisher: Elsevier Science
• Year: 1969
• Tongue: French
• Weight: 205 KB
• Volume: 10
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)88811-0

✦ Synopsis

During studies of photo-additions of diphenylacetylene (DPA) to aromatic hydrocarbons we examined the effects of Pyrex-filtered U.V. light on mixtures of DPA and benzo[b]thiophen(l).

We now report the formation of two 1:l photo-adducts (I) and (II) in these reactions, and the photo-isomerisation of adduct (I) to adduct (II). We also record differences in the thermal stabilities of adducts (I) and (II). Our findings have a bearing on the recent report by Neckers, Dopper and Wynberg (2) concerning the formation of adduct (III) from dimethyl acetylenedicarboxylate and benzo[b]thiophen.

These authors did not adduce any evidence for the fbrmation of the isomeric adduct (IV) in this reaction but the present results support their suggestion that (III) could be derived from a primary adduct (IV) by photo-isomerisation.