Photochemical Behavior of 2,5-Di-tert-butyl-3H-azepine: Unexpected Formation of a Dicyclopenta[b,e]pyridine Derivative and a cis,cis-Cyclodeca-1,6-diene Derivative.

Hitherto unknown photochemical behavior of 3H-azepine giving cyclopent[c]azete and a (4π + 4π) photodimer is reported on the basis of an unexpected formation of a tricyclic dicyclopenta[b,e]pyridine derivative and a ten-membered-ring dicarbaldehyde by irradiation of 2,5-di-tert-butyl-3H-azepine in hexane.