Photochemistry of Succinimides with a Cycloalkenylalkyl Group in the Side Chain. Competitive Norrish Type II and Paterno-Buchi Reactions

Abstract

Photolysis of N-[ω-(cycloalken-1-yl) alkyl] succinimides (9c-f) (m≨2) afforded mainly azepinediones (13c-f) with ring enlargement as the Norrish type II cyclization products. In the case of m=1, spiro-azepinedione derivatives (11a, b) were obtained in addition to tricyclic nitrogen heterocycles (10a, b), the Norrish type II products. These spiro-azepinediones are probably formed via imide-oxetanes by the intramolecular Paterno-Buchi reaction of these succinimides in competition with the type II processes.