Kleine Ringe, 76[1]. Zwischenstufen auf dem Wege zum Cyclopentadienontetracarbonsäuretetramethylester
✍ Scribed by Maier, Günther ;Wilmes, Rolf
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1993
- Tongue
- English
- Weight
- 449 KB
- Volume
- 126
- Category
- Article
- ISSN
- 0009-2940
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✦ Synopsis
Ester migration / Cyclopentadienone dimer Small Rings, ?6[11. -Intermediates on the Way to Tetramethyl Cyclopentadienonetetracarboxylate "Potassium salt" 6, already described by Cookson, reacts with suitable electrophilic reagents to yield the enol esters 8-10.
A base-catalyzed acylation of the hydroxy group in 8-10 cannot be achieved because deprotonation is immediately fol-lowed by a [l,5] ester migration. The same reaction occurs upon heating 8-10 to 80°C, leading to the 1J-keto enols 11, 12, and 14. Upon treatment of "alcohol" ? with acetyl chloride only the dimer 3 of cyclopentadienone 2 can be isolated.