Photochemical 1,3-acyl migration in cyclic dienamides (azepinones)

✍ Scribed by Hans-Dieter Becker; Alan B. Turner

• Publisher: Elsevier Science
• Year: 1979
• Tongue: French
• Weight: 216 KB
• Volume: 20
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)86736-8

✦ Synopsis

Irradiation of 1,3-dihydro-2lJ-azepin-2-ones in aprotic solvents gives azabicycloheptenones by intramolecular cycloaddition, but photochemical isomerization in methanol results in 1,3-acyl migration involving cleavage of the amide bond.

Seven-membered heterocycles containing a conjugated diene system readily undergo photochemical valence isomerization to give annelated cyclobutenes.