Mining the Tetraene Manifold: Total Synthesis of Complex Pyrones from Placobranchus ocellatus

A natural product anticipated through total synthesis! Ocellapyrone A was obtained in the laboratory several months before the structure of this unusual natural product (see scheme) was reported. An isomerization/8π–6π electrocyclization cascade was used for the formation of the natural product from a polyene precursor. The synthesis of ocellapyrone B from a diastereomer of ocellapyrone A was also performed.