Bio-inspired construction of a tetracyclic ring system with an avarane skeleton: total synthesis of dactyloquinone A

The asymmetric synthesis of the marine meroterpenoid dactyloquinone A was accomplished for the first time. The key advanced intermediate, a 6/6/6/6 tetracyclic core derivative, was constructed by a bio-inspired Lewis acid-catalyzed cyclization reaction, which drove the migration of the methyl groups of two different configurations at the C-4 site by 1,2-rearrangement from the aureane skeleton to the avarane skeleton. This strategy sets the stage for the synthetic exploration of other members of this family of natural products.