Crystal structure and Hirshfeld analysis of (1aS,3aR,4aS,5aR)-15-acet­oxy­linden-7(11),8-trieno-12,8-lactone

The structure of the title com­pound, C(17)H(20)O(4) [systematic name: (1aS,3aR,4aS,5aR)-15-(acet­oxy)linden-7(11),8-trieno-12,8-lactone or (4aR,5S,5aR,6aS,6bR)-5-(acet­oxy­meth­yl)-4a,5,5a,6,6a,6b-hexa­hydro-3,6b-di­methyl­cyclo­propa[2,3]indeno­[5,6-b]furan-2(4H)-one, ent-chloranthalactone C], a natural product iso­lated from the whole plant Chloranthus japonicus Sieb., is a typical lin­den­ane-type sesquiterpenoid. The mol­ecule com­prises a bi­cyclo­[3.1.0]hexane ring (A/B system) bearing an acetoxymethyl (C-4) group, a bi­cyclo­[4.3.0]nonane ring (B/C system) containing a double bond (C-8/9) and a chiral quaternary carbon (C-10), and a 7(11)-en-12,8-olide structural moiety on the cyclo­hexan-8-ene (C ring). In the tetra­cyclic skeleton, the 1,3-cyclo­propane ring has a β-con­figuration, and atoms H-5 and H(3)-14 have α- and β-orientations, respectively. In the crystal, the mol­ecules are assembled into a two-dimensional network by weak O⋯H/H⋯O inter­actions. Hirshfeld surface analysis illustrates that the greatest contributions are from H⋯H (55.2%), O⋯H/H⋯O (34.6%) and C⋯H/H⋯C (8.9%) contacts.