Aromatic Sulfonation, 130. – Relative Intramolecular Reactivity of the Insulated π Double Bond and the 14π Annulene Perimeter toward Sulfur Trioxide in the Sulfonation of Isopyrenes
✍ Scribed by Cerfontain, Hans ;Bakker, Bert H. ;Koeberg-Telder, Ankie ;Wilmes, Oswald
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 471 KB
- Volume
- 1997
- Category
- Article
- ISSN
- 0947-3440
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✦ Synopsis
Abstract
The sulfonation of isopyrene (1) and its 5‐methyl‐ and 5,10‐dimethyl derivative 2 and 3 with SO~3~ in both dichloromethane and nitromethane as solvent has been studied. Reaction of 1 and 2 leads to sulfodehydrogenation in which SO~3~ reacts as a monodentate electrophile, the initial products being 1‐5‐sulfonic acid (1‐5‐S) and 2‐10‐S, respectively. In the presence of a sufficiently large amount of SO~3~ 1‐5‐S is subsequently converted into 1‐5,10‐S~2~. With 3, using 2.0 molequiv, of the sulfonating reagent in dichloromethane, the SO~3~ adds as a bidentate electrophile to the “central C=C bond” with formation of 7,14‐dimethyl‐1,6:8,13‐ethanediylidene‐[14]annulene‐15,16‐sultone (5) and the corresponding pyrosultone 6. Upon subsequent hydrolysis and neutralization with aqueous KOH the eventually obtained product is potasium 16‐hydroxy‐7,14‐dimethyl‐1,6:8,13‐ethanediylidene‐[14]annulene‐15‐sulfonate (4).