Annulative π-Extension by Cp*Co(III)-Catalyzed Ketone-Directed peri -Annulation: An Approach to Access Fused Arenes.

A masked-bay-region selective first-row transition-metal Cp*Co(III)-catalyzed annulative π-extension of arene-derived ketones is achieved to afford K-region-functionalized benzo[ e ]pyrenes, benzotetraphenes, and pyrenes. Comprehensive density functional theory studies buttress the mechanistic pathway comprising key steps like peri -C-H activation, alkyne 1,2-migratory insertion, and nucleophilic attack toward ketone, this attack being the rate-determining step. In addition, π-conjugated 1,1'-bipyrenes, potential photocatalyst pyrene-quinones, and putative n-type semiconductor cyano group-containing dibenzo[ de , qr ]tetracenes are also accessed.