Hawaiienols A–D, Highly Oxygenated <i>p</i>-Terphenyls from an Insect-Associated Fungus, <i>Paraconiothyrium hawaiiense</i>

Abstract

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[3.2.1.0^3,6]octane unit in its p-terphenyl skeleton and showed cytotoxicity toward six human tumor cell lines.