Total syntheses of shizukaols A and E

摘要

Shizukaols possess a common heptacyclic framework containing more than ten contiguous stereocenters and potential biological activities. Here we report that the total syntheses of shizukaols A (>1) and E (>2), two lindenane-type dimers from the Chloranthaceae family, are achieved via a modified biomimetic Diels–Alder reaction. The common crucial biomimetic diene >23 and ethylene species (>6, >17) are obtained through either a highly Z-selective olefination of α-siloxy ketone with ynolate anions or an intramolecular Horner–Wadsworth–Emmons olefination from commercially available Wieland–Miescher ketone (>7). This synthetic approach here opens up practical avenues for the total syntheses of the intriguing Chloranthaceae family members, as well as the understanding of their relevant biological action in nature.