Neosartoricin D is an acetal-containing dioxabicyclo-octanone ring, resulting from an intramolecular hydroxyl attack on neosartoricin C. The neosartoricins are cryptic fungal metabolites produced on inserting a conserved gene cluster from strains of Trichophyton and Arthroderma into an Aspergillus nidulans host. The biological activity of neosartoricin D remains to be determined.