Photochemical cyclodimerisation and rearrangement of 5H-dibenz[b,f]azepine derivatives

Abstract

Unsensitised and benzophenone-sensitised irradiation of N-acyl, -aroyl, and -ethoxycarbonyl derivatives of 5H-dibenz[b,f]azepine (1)(iminostilbene) gives good yields of cyclobutane dimers (2); the parent compound and its N-alkyl derivatives are photochemically inactive, whereas the N-tosyl compound undergoes photo-Fries rearrangement.