Weak Base-Promoted Direct Cross-Coupling of Naphthalene-1,8-diaminato-substituted\nArylboron Compounds

The indispensability\nof a base in Suzuki–Miyaura coupling\n(SMC) employing organoboronic acids/esters is well recognized, which\noccasionally induces competitive protodeborylation in organoboron\nreagents. This phenomenon is particularly pronounced in fluorine-substituted\naryl and heteroaryl boron compounds. Here, we show that direct SMC\nof naphthalene-1,8-diaminato (dan)-substituted aryl boron compounds,\nAr–B(dan), characterized by its remarkable stability toward\nprotodeborylation due to their diminished boron-Lewis acidity, occurs\nutilizing a weak base in conjunction with a palladium/copper cooperative\ncatalyst system. The approach delineated in this study enables the\nefficient incorporation of various perfluoroaryl– and heteroaryl–B(dan)\nreagents, while maintaining high functional group tolerance. Furthermore,\nthe inherent inertness of the B(dan) moiety allowed sequential cross-coupling,\nwhere other metallic moieties chemoselectively undergo the reaction,\nthus leading to the concise, protection-free synthesis of oligoarenes.\nOur results provide a potent approach to a delicate dilemma between\na protodeborylation-resistant property and SMC activity intimately\nlinked to boron-Lewis acidity.