Hawaiienols A–D, Highly Oxygenated p‑Terphenyls from an Insect-Associated Fungus, Paraconiothyrium hawaiiense

Four new highly oxygenated p-terphenyls, hawaiienols A–D (1–4), have been isolated from cultures of Paraconiothyrium hawaiiense, a fungus associated with the Septobasidium-infected insect Diaspidiotus sp.; their structures were elucidated primarily by NMR experiments. The absolute configurations of 1 and 2–4 were assigned by single-crystal X-ray diffraction analysis using Cu Kα radiation and via electronic circular dichroism calculations, respectively. Compound 1 incorporated the first naturally occurring 4,7-dioxatricyclo­[3.2.1.03,6]­octane unit in its p-terphenyl skeleton and showed cytotoxicity toward six human tumor cell lines.