Electrochemically generated bromine for direct and mediated organic synthesis

Abstract

This Ph.D. work focused on the development of new synthetic approaches in direct electrochemical bromination and bromine-mediated synthesis. The superiority of electrochemical bromination over the traditional methods was demonstrated using a safe and inexpensive alternative, sodium bromide, as an in-situ-generated bromine surrogate and supporting electrolyte in a dual role. A more sustainable and greener electrochemical dibromination method was successfully developed, focusing on naturally derived alkenes as precursors. The applicability of a terpene-based organobromine was demonstrated via a subsequent functionalization to an a,b-unsaturated nitrile for the first time. These results encouraged further studies for the bromocyclization of alkenoic acids and the selective a-bromination of electrondeficient enones. Finally, a possible bromine-mediated electrochemical Hofmann rearrangement of urea derivatives to hydrazines was investigated, furnishing the unexpected azobenzene products.