Phenanthro[9,10-a]corannulene by one-step annulative π-extension of corannulene

The one-step pi-extension of corannulene was achieved using a palladium-catalyzed C-H coupling reaction. The X-ray crystal structure and photophysical properties of the thus formed phenanthro[9,10-a]corannulene (1) were investigated, and the structural properties of 1 were examined by density functional theory calculations. In contrast to dibenzo[g,p]chrysene, the most stable structure of 1 was a butterfly-shaped structure, resulting from the bowl-shaped distortion of the corannulene moiety.