Assembly of Fluoranthenes via Cobalt-Catalyzed [2 + 2 + 2] Cycloaddition of 1,6-Diynes with Alkynes

A series of polyaryl-substituted fluoranthenes is built in good to excellent yields via Earth-abundant metal-catalyzed [2 + 2+ 2] cycloaddition of 1,6-diynes with alkynes is developed. This method runs smoothly using a cheap catalytic system (CoI₂/dppe/Zn) as the catalyst. Generally, this strategy exhibits low cost, high efficiency, good atom economy, and good functional group tolerance. Additionally, both terminal alkynes, especially heteroaryl-substituted acetylenes, and internal alkyne, tolerate smoothly in this work. Furthermore, the photophysical properties of the selected fluoranthenes is also investigated.