Treatment of o-iodobiphenyls with o-bromobenzyl alcohols in the presence of cesium carbonate under palladium catalysis affords a series of highly substituted triphenylenes. The reaction involves two C-C bond formations and C-C and C-H bond cleavages. A combination of palladium and an electron-deficient phosphine ligand proves to be effective for both decarbonylative cross-coupling and intramolecular cyclization.

o-Bromobenzyl alcohol has been developed as a novel annulating reagent, bearing both nucleophilic and electrophilic substituents, for the facile synthesis of polycyclic aromatic hydrocarbons. A palladium/electron-deficient phosphine catalyst efficiently coupled o-iodobiphenyls or (Z)-β-halostyrenes with o-bromobenzyl alcohols to afford triphenylenes and phenanthrenes, respectively. The present cascade reaction proceeded through deacetonative cross-coupling and sequential intramolecular cyclization. An array of experimental data suggest that the reaction mechanism involves the equilibrium of 1,4-palladium migration.

Complex. -o-Bromobenzyl alcohols are introduced as new annulation reagents, which facilitate the annulation of o-iodobiphenyls and (Z)--halostyrenes to afford triphenylenes and phenanthrenes, respectively. This protocol enables the synthesis of highly fused -conjugated molecules bearing various functional groups. -(IWASAKI, M.; ARAKI, Y.; IINO, S.; NISHIHARA*, Y.; J. Org. Chem. 80 (2015) 18, 9247-9263, http://dx.doi.org/10.

Palladium-Catalyzed Annulation of o-Iodobiphenyls with o-Bromobenzyl Alcohols: Synthesis of Functionalized Triphenylenes via C-C and C-H BondCleavages. -(IWASAKI, M.; IINO, S.; NISHIHARA*, Y.; Org. Lett. 15 (2013) 20, 5326-5329, http://dx.