The zwitterionic intermediates (2a) in the oxidation of ortho-alkylphenols (1) and bis (sulfonium ylide) 3 form reasonably stable 2: 1-complexes (4), in which the ortho-quinone methide (oQM) moieties are not present in quinoid form with the exocyclic in-plane methylene group, but as zwitterionic, aromatic conformer having an out-of-plane exocyclic methylene group. The complex 7 derived from the α-tocopherol model compound PMC (5) ...
![1-[3-[[2,4-Dihydroxy-6-methoxy-5-methyl-3-(1-oxobutyl)phenyl]methyl]-2,4,6-trihydroxy-5-methylphenyl]-1-butanone Structure](https://image.chemsrc.com/caspic/251/1867-82-9.png)