Halogenation of cyclic olefins containing spiroconjugated imidazolone moiety

Abstract

The electrophilic halogenation of spirocyclic olefins containing an imidazolone fragment were studied using techniques of dropwise addition of halogen and diffusion mixing with halogen vapor. The bromination reactions providing the formation of trans-1,2-dihalogenation products (when reactions with bridging olefin are carried out in chloroform) or skeletal rearrangements (reactions in acetonitrile or methanol) are most chemo- and stereoselective. Chlorination is nonselective with the formation of mixtures of products, and success of iodination is determined by the choice of the substrate and reaction conditions.