Use of 2‑Bromophenylboronic Esters as Benzyne Precursors in the Pd-Catalyzed Synthesis of Triphenylenes

<i>ortho</i>-Substituted aryl boronates are introduced as aryne precursors for transition-metal-catalyzed transformations. On treatment with <sup><i>t</i></sup>BuOK and Pd(0), metal-bound aryne intermediates are formed that undergo effective trimerization to form useful triphenylene compounds. For <i>meta</i>-substituted arynes, the 3:1 product ratio in favor of non-C<sub>3</sub> symmetric material is indicative of a benzyne mechanism.