The Inherent Competition between Addition and Substitution Reactions of Br₂ with Benzene and Arenes

Abstract

Tug of war: Comprehensive DFT computational exploration of the reaction mechanisms predicts that the barriers for Br2 addition processes to benzene, naphthalene, anthracene, and phenanthrene in isolation (i.e., in the absence of catalysts, see picture) and in simulated CCl4 solution can be even lower than the barriers for direct substitution. Moreover, substitution products also can arise from stepwise Br2 addition–HBr elimination routes.