Stereoselective Total Synthesis of (±)-5-epi-Cyanthiwigin I via an Intramolecular Pauson–Khand Reaction as the Key Step

A convenient approach to the construction of the 5–6–7 tricarbocyclic fused core structure of cyanthiwigins via a Co-mediated Pauson–Khand reaction as a key step has been developed. The cyathane core intermediate obtained by this strategy was used in the concise synthesis of (±)-5-epi-cyanthiwigin I. The developed chemistry paves the way for the total synthesis of structurally diverse cyanthiwigins.