Direct bromocarboxylation of arynes using allyl bromides and carbon dioxide.

An unprecedented three-component coupling involving arynes, allyl bromides, and CO2 is described, providing efficient and facile access to structurally diverse ortho-brominated aryl esters. Unlike the conventional role played in organic synthesis as electrophiles, organic bromides served as nucleophiles in this reaction, affording a new approach to multicomponent reactions (MCRs) involving aryne intermediates. Additionally, Hammett analysis suggests that two reaction mechanisms exist, depending on the electronic nature of the cinnamyl bromides used.