V. Veprek‐Bilinski, K. Narasimhan, A. Dreiding
Dec 13, 1978
Citations
0
Influential Citations
4
Citations
Journal
Helvetica Chimica Acta
Abstract
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.