Reactivity of Aryldimesitylboranes under Suzuki−Miyaura Coupling Conditions

Sterically protected triarylboron compounds such as BMes2(Ar) have important applications in organic optoelectronic devices and chemical sensors. Furthermore, the Suzuki−Miyaura cross-coupling reaction is the most commonly used method for building the π skeletons of such conjugated materials. We have found that BMes2(Ar) can also be a highly active and effective coupling partner under typical Suzuki−Miyaura coupling conditions. For BMes2(p-Br-Ph), self-coupling leads to the formation of oligomers Mes2B−(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 BMes2(Ph) with various aryl bromides has established the generality of BMes2(Ar) as a coupling partner.