Total Synthesis of (±)‐Waihoensene

The first total synthesis of waihoensene, a tetracyclic diterpene containing an angular triquinane and a six‐membered ring, with four contiguous quaternary carbon atoms, was achieved through the tandem cycloaddition reaction of an allenyl diazo substrate containing a six‐membered ring via trimethylenemethane (TMM) diyl intermediate.