Synthesis of neoflavenes by ligand coupling reactions with aryllead triacetates

The reaction of 4-methoxycarbonylchroman-3-one with aryllead triacetates ga ve the 4-aryl derivatives after 3-4 h reaction times in moderate to good yi elds. Unexpectedly, 2,4-diarylated derivatives were also obtained after lon ger reaction times. The activating methyl ester group proved difficult to r emove by standard decarboxylation procedures. 4-Benzyloxycarbonylchroman-3- ones were therefore prepared and reacted with aryllead triacetates to affor d the corresponding 4-aryl derivatives. These were subsequently decarboxyla ted, reduced and dehydrated to afford neoflavenes in modest overall yields. (C) 2000 Elsevier Science Ltd. All rights reserved.