Gymnoascolides A−C: Aromatic Butenolides from an Australian Isolate of the Soil Ascomycete Gymnoascus reessii

Three new aromatic butenolides, gymnoascolides A−C (1−3), have been isolated from the Australian soil ascomycete Gymnoascus reessii and assigned structures on the basis of detailed spectroscopic analysis. The absolute configurations of gymnoascolides B (2) and C (3) at C-5 were solved using a combination of chemical derivatization and quantum chemical simulations.