Total Synthesis of Kingianins A, D, and F

A synthesis fit for a king: The total synthesis of (±)-kingianins A, D, and F has been achieved in ten steps. Key features include the gram-scale synthesis and partial reduction of a conjugated tetrayne to a (Z,Z,Z,Z)-tetraene, the domino 8π–6π electrocyclic ring closure of a (Z,Z,Z,Z)-tetraene, and the radical-cation-catalyzed formal Diels–Alder dimerization of functionalized bicyclo[4.2.0]octadiene precursors.