Experiments towards the Synthesis of the Ergot Alkaloids and Related Structures.Part 7.1 Novel Syntheses of some 4-Acyl-2,3,4,4a,5,6-hexahydrobenzo[f]quinolin-2-ones

Abstract

Reaction of the N-formyl enol-lactone 4 and the corresponding N-acetyl 10 and N-methoxycarbonyl 11 derivatives with bis(trimethylsilyl)potassiomalonate in THF at 60°C followed by treatment with aqueous sodium hydrogen carbonate and cyclisation as above, yielded the 4-formyl-, 4-acetyl- and 4-methoxycarbonyl-tricyclic ketones 7, 13 and 14 in yields of 31, 35 and 36%, respectively.