Abstract:

Super bowl: Bicorannulenyl, a large biaryl composed of two corannulene bowls, effectively becomes an overcrowded ethylene upon reduction to form a dianion (see picture). DFT calculations and NMR spectroscopic experiments reveal the double-bond character of the connection between the two bowls. Three stable diastereomers that interconvert through bowl inversions and central bond rotations were shown to exist.