✦ LIBER ✦
Stabilization of ortho-quinone methides by a bis(sulfonium ylide) derived from 2,5-dihydroxy-[1,4]benzoquinone
✍ Scribed by Anjan Patel; Thomas Netscher; Thomas Rosenau
- Publisher
- Elsevier Science
- Year
- 2008
- Tongue
- French
- Weight
- 158 KB
- Volume
- 49
- Category
- Article
- ISSN
- 0040-4039
No coin nor oath required. For personal study only.
✦ Synopsis
The zwitterionic intermediates (2a) in the oxidation of ortho-alkylphenols (1) and bis(sulfonium ylide) 3 form reasonably stable 2:1complexes (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 atocopherol model compound PMC (5) was comprehensively characterized. As exemplarily demonstrated, the adducts can be advantageously employed in organic synthesis as 'stabilized oQMs'.