Microscale synthesis of bromo- and bromochloro-dibenzo-p-dioxins and dibenzofurans

Abstract

The synthesis of polybromo-and polybromochloro-dibenzo-p-dioxins and dibenzofurans by electrophilic halogenation of unsubstituted precursors with iron (III) halides (in the absence of halogen) is described. Reaction in sealed tubes was found to give higher yields than open-tube reactions. Temperature, reaction time and reagent and starting material proportions were optimised, allowing the synthesis of mono- through octa-substituted products in high overall yield (>33%).