抗インフルエンザＡウイルス活性物質スタキフリンの全合成

抄録

(+)-Stachyflin, isolated from the Stachybotrys sp. RF-7260, was found to be a novel anti-influenza A virus activity by the Shionogi research group in 2002. Structurally, stachyflin consists of a novel pentacyclic benzo[d]xanthene skeleton (ABCDE ring system), in which cis-fused AB and BC rings, and an ether bond at the bridgehead of the decalin ring junction are characteristic features. We have achieved the total synthesis of (+)-stachyflin starting from the known (+)-Wieland-Mischer keton derivative. The key steps of this synthesis are (i) coupling reaction of the (+)-Wieland-Mischer ketone derivative with the isoindolinone segment, (ii) sequential BF₃·OEt₂-induced epoxy rearrangement/cyclization reaction, and (iii) deprotection of the N-3,4-dimethoxybenzyl (DMB) group using hypervalent iodine reagent PIFA.