Synthesis of Dibenzo-fused Corannulenes

We removed the top and bottom radialene units of the fullerene molecule to generate [10]cyclophenacene as described above. An alternative view of [60]fullerene may generate hemispherical bowl-shaped aromatic systems [lc, 37] for instance, fused corannulene C (C30H12, Chart 2.1), can be identified as half of fullerene [38]. 

The X-ray crystallographic analysis of 9 provided experimental structural data of the new corannulene-type aromatic system. The bond alternation found in 9 closely follows the pattern found in an X-ray crystal structure of tetramethyl fused corannulene [38c]. Such agreement of the bond alternation patterns indicates that the fullerene framework and the dibenzo conjugation added to the parent corannulene structure have a small structural effect in spite of the rather large difference in hybridization of the carbon atoms between 9 p-orbital axis vector (POAV) angles [40] = 8.0-12.8° and C (POAV = 0.0-11.0°). 

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