Evidence for the Möbius aromatic character of eight π electron conrotatory transition structure. Magnetic criteria

The Möbius aromatic character of the 8π electron transition structure for the conrotatory electrocyclic ring closure of (Z,Z)-octa-1,3,5,7-tetraene is demonstrated by downfield and upfield 1H chemical shifts as well as the enhanced magnetic susceptibility computed by the IGLO method. H1,8 (outer) are deshielded and H1,8 (inner) are shielded in the transition structure.