Zur Reaktionsweise von Diphenylcyclopropenon mit β-Carbonyl-enolaten. I. Einsatz von Acetylaceton, Acetessigsäure-methylester, 2-Äthoxycarbonyl-cyclododecanon und Malonsäure-dimethylester
✍ Scribed by Vanda Veprek-Bilinski; Krishna Narasimhan; André S. Dreiding
- Publisher
- John Wiley and Sons
- Year
- 1978
- Tongue
- German
- Weight
- 527 KB
- Volume
- 61
- Category
- Article
- ISSN
- 0018-019X
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✦ Synopsis
Reaction of Diphenylcyclopropenone with β‐Carbonyl‐enolates. I. Use of Acetylacetone, Methyl Acetoacetate, 2‐Ethoxycarbonyl‐cyclododecanone and Dimethyl Malonate
The reaction of the sodium salts of acetylacetone (6), methyl acetoacetate (7), 2‐ethoxycarbonyl‐cyclododecanone (8), dimethyl malonate (19) and its methyl derivative 20 with diphenylcyclopropenone (5) in dimethylformamide at room temperature led to the unsaturated γ‐lactones 14, 15, 17, 22 and 36. In the case of dimethyl malonate (19), the halfester 21, the acyl‐malonic ester 24 and the indenone‐malonic ester 23 were also isolated.
Several intermediates and the final products were characterised by reactions and spectroscopically. A general mechanism is discussed for the addition of cyclo‐propenones (1) to the enolate salts of β‐dicarbonyl compounds 4 involving the bicyclic lactone‐enolates 18 and 32 as intermediates. The products formed via 18 and 32 are considered to be the result of an attack of one of the oxygen atoms of the β‐carbonyl‐enolate anion (4), the product 24, on the other hand, of the attack of the α‐carbon atom of 4; in both cases the attack is on the carbonyl C‐atom of 5.