9a-Hydroxy-3,8a-dimethyl-5-methylene-4,4a,5,6,9,9a-hexahydronaphtho[2,3-b]furan-2(8aH)-one

The title compound, C15H18O3, was isolated from Lactarius piperatus (Fr.) S. F. Gary collected from the Kunming area in Yunnan province, China. The central cyclohexyl ring adopts a chair conformation, while the furanone ring is close to planar (r.m.s. deviation = 0.0174 angstrom). The remaining methylene cyclohexene ring has a flattened chair conformation. In the crystal, molecules are linked via intermolecular O-H center dot center dot center dot O and C-H center dot center dot center dot O hydrogen bonds into zigzag chains along the a axis.