Bridge of Si: Intramolecular direct arylation of 2‐(arylsilyl)aryl triflates is catalyzed smoothly by Pd(OAc)2/PCy3 in the presence of Et2NH in dimethylacetamide (DMA), giving rise to the corresponding silicon‐bridged biaryls in good to excellent yields. The new approach has led to the synthesis of a silicon‐bridged 2‐phenylindole (see scheme) that exhibits blue photoluminescence in the solid state with extremely high quantum yields.

We have discovered that the combination of Pd(OAc)(2)/o-chloranil can catalyze the direct C-H bond arylation of polycyclic aromatic hydrocarbons (PAHs) with arylboroxins that occurs selectively at the K-region. The sequential integration of Pd-catalyzed direct arylation of PAHs and FeCl(3)-mediated cyclodehydrogenation is effective in rapidly extending a parent PAH π-system with high directionality.

Palladium-catalyzed intramolecular direct arylation of 2-[(2-pyrrolyl)silyl]aryl triflates gives 3,2'-silicon-bridged 2-arylindoles and -pyrroles in good to high yields. The reaction proceeds through cleavage of C-OTf, C-Si, and C-H bonds to result in the formation of C-C and C-Si bonds. Various kinds of functional groups such as OMe, CN, Cl, F, and SiMe(3) tolerated the conditions. The new reaction allows synthesis of functionalized Si-bridged 2-arylindoles that emit intense and efficient blue fluorescence in the solid state.