Affiliation:
1. Welsh School of Pharmacy, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff CF1 3XF, UK
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.