Crystal structure and Hirshfeld surface analysis of (5a S ,8a R )-3,5a-dimethyl-8-methyl-idene-2-oxododeca-hydro-oxireno[2',3':6,7]naphtho-[1,2- b ]furan-6-yl ( Z )-2-methyl-but-2-enoate extracted from Ferula persica .

In the title compound, C 20 H 26 O 5 , the two cyclo-hexane rings adopt boat and half-chair conformations. In the crystal, adjacent mol-ecules are connected by inter-molecular C-H⋯O hydrogen bonds, forming a three-dimensional network. According to a Hirshfeld surface study, H⋯H inter-actions are the most significant contributors to the crystal packing (63.0%).