Reactivity of Aryldimesitylboranes under Suzuki-Miyaura Coupling Conditions

Sterically protected triarylboron compounds such as BMes(2)(Ar) have important applications in organic optoclectronic devices and chemical sensors. Furthermore, the Suzuki-Miyaura cross-coupling reaction is the most commonly used method for building the pi skeletons of such conjugated materials. We have found that BMes(2)(Ar) can also be a highly active and effective coupling partner under typical Suzuki-Miyaura coupling conditions. For BMes(2)(p-Br-Ph), self-coupling leads to the formation of oligomers Mes(2)B-(Ph)(n)-Mes, where the products with n = 1 (1), 2 (2), 3 (3), 4 (4) have been isolated and fully characterized. Examination of cross-coupling reactions of BMes(2)(Ph) with various aryl bromides has established the generality of BMes(2)(Ar) as a coupling partner.