Structurally Diverse Meroterpenoids from a Marine-Derived <i>Aspergillus</i> sp. Fungus

Abstract

Three new meroterpenoids, asperaustins A-C (<b>1</b>-<b>3</b>), and seven known analogues (<b>4</b>-<b>10</b>) were isolated from a marine-derived <i>Aspergillus</i> sp. fungus. The structures and absolute configurations of these new compounds were unequivocally determined by extensive spectroscopic analyses and single-crystal X-ray diffraction analyses. Asperaustin A (<b>1</b>) possesses an unusual spiro[4.5]deca-3,6-dien-2-one moiety with a unique 5/6/6/6/5 pentacyclic skeleton. The absolute configurations of austinoneol A (<b>7</b>) and precalidodehydroaustin (<b>9</b>) were determined by single-crystal X-ray diffraction analyses using Cu Kα radiation for the first time.