Use of 2-bromophenylboronic esters as benzyne precursors in the Pd-catalyzed synthesis of triphenylenes

ortho-Substituted aryl boronates are introduced as aryne precursors for transition-metal-catalyzed transformations. On treatment with tBuOK and Pd(0), metal-bound aryne intermediates are formed that undergo effective trimerization to form useful triphenylene compounds. For meta-substituted arynes, the 3:1 product ratio in favor of non-C3 symmetric material is indicative of a benzyne mechanism. © 2014 American Chemical Society.