Beyond Corannulene

NMR evidence shows that 15 is indeed bowl-shaped with the bowl-to-bowl inversion barrier significantly higher than corannulene [18]. 

Later we also managed to synthesize 16 by a nonpyrolytic route [14aj. The synthesis started with known 1,3,6,8-tetramethylnaphthalene 18, and subsequent low-valent vanadium coupling of the dibromomethyl groups of dodecabromide 19 gave 

Very recently the crystal structure of the other semibuckminsterfullerene 20 was determined by X-ray study in the Petrukhina laboratory [25]. Unfortunately the random distribution of both enantiomers of the chiral hydrocarbon precluded the precise determination of the molecular geometry, but allowed observation of the packing patterns in two different polymorphs that revealed an endo-exo stacking of the bowls of 20 in one of them [25]. 

Rim-benzoannulated corannulenes have been of interest since they represent an obvious extension of the fullerene surface and could potentially serve as precursors for larger bowl syntheses. Several of these derivatives including benzocorannulene 23 [26], dibenzo[a,d]corannulene 24 [26a], dibenzo[a,g]corannulene 25 [16, 27] and tribenzo[a,d,j]corannulene 26 [26] were recently synthesized by FVP and/or non-pyrolytic methods. X-ray crystal structure determination of 25 was very recently achieved [28] on a crystal grown by sublimation and revealed an assembling of 

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