Kinetics and mechanism of bromination of cyclic acetals with 1,4-dioxane dibromide

Article abstract of DOI:10.1007/BF00507239

It is shown that the reactivities of cyclic formals in the case of bromination with dioxane dibromide increase in the order 1,3-dioxepane > 1,3-dioxalane ? 1,3-dioxane, which is explained not only by steric factors but also by the ease of cleavage of the C₄-O₃ bond of the dioxacyclane ring. The bromination of cyclic acetals takes place through prior enolization of the cyclic acetal with subsequent electrophilic addition of bromine to the double bond.