Vicinal Vinylation of Boron-Doped Acenes via Heck Coupling

Silylated and halogenated benzenes 1,2-(Me3Si)2-4,5-X2-C6H2 [X =
Br (3), I (4)] are versatile synthetic building
blocks. 3 was prepared from known 1,2-(Me3Si)2-4,5-Cl2-C6H2 via
C–Cl borylation/bromodeboronation;
CuI-catalyzed Br/I exchange on 3 affords 4. 3 or 4 and BBr3 yield 9,10-dibromo-9,10-dihydro-9,10-diboraanthracenes
(DBAs) 7 or 8. The B centers were protected
with mesityl (Mes; 9, 10) or 2,4,6-tris(trifluoromethyl)phenyl
(FMes; 11, 12) groups. Heck coupling
of 9 and styrene/2,3,4,5,6-pentafluorostyrene furnishes
the two tetravinyl-substituted green/blue emitters 13/14.