A preferred disrotatory 4n electron Möbius aromatic transition state for a thermal electrocyclic reaction.
Not 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.
Mauksch
Michael
M
Department Chemie und Pharmazie, Lehrstuhl für Organische Chemie I, Universität Erlangen-Nürnberg, Henkestrasse 42, 91054 Erlangen, Germany.
Tsogoeva
Svetlana B
SB