A unified approach to meroterpenoids applanatumols B, V, W, X, and Y produced by the medicinal fungus Ganoderma applanatum and 2'-epi-spiroapplanatumine O is presented. The key synthetic sequence consists of a tandem anionic ketone allylation/oxy-Cope rearrangement/alpha-oxygenation furnishing an alpha-aminoxy ketone and a persistent radical effect-based 5-exo-trig cyclization leading to the trisubstituted cyclopentane core.
The relative configuration of applanatumol V has to be revised. Some compounds display significant cytotoxic and antioxidant properties.