Mauksch and Tsogoeva have recently published an article illustrating how a thermal electrocyclic reaction can proceed with distoratory ring closure, whilst simultaneously also exhibiting 4n electron Möbius-aromatic character[cite]10.1002/anie.200806009[/cite]. Why is this remarkable?
AbstractNot forbidden: Thermal 4n electron electrocyclic reactions of Hückel topology structures proceed via “allowed” conrotatory pathways. However, for a Möbius topology, the Woodward–Hoffmann rules may be reversed and a “forbidden” disrotatory pathway can be preferred as shown theoretically for dodecahexaene 1 that transforms via a Heilbronner–Möbius aromatic transition structure 2 into a cyclic polyene 3.magnified image