The First Naturally Occurring Thiepinols and Thienol from an Endolichenic Fungus <i>Coniochaeta</i> sp.

Coniothiepinols A (1) and B (2) and coniothienol A (3), the first naturally occurring thiepinols (1 and 2) and thienol (3), have been isolated from the crude extract of an endolichenic fungus Coniochaeta sp. 1 possesses a unique 8-oxa-2-thia-bicyclo[3.2.1]octane skeleton, and its structure was assigned by NMR spectroscopy and X-ray crystallography. 1 showed significant activity against the Gram-positive bacteria, Enterococcus faecium and Enterococcus faecalis.