Crystal structure and Hirshfeld analysis of (1a,3a,4a,5a)-15-acet-oxy-linden-7(11),8-trieno-12,8-lactone.

The structure of the title com-pound, CHO [systematic name: (1a,3a,4a,5a)-15-(acet-oxy)linden-7(11),8-trieno-12,8-lactone or (4a,5,5a,6a,6b)-5-(acet-oxy-meth-yl)-4a,5,5a,6,6a,6b-hexa-hydro-3,6b-di-methyl-cyclo-propa[2,3]indeno-[5,6-]furan-2(4)-one, -chloranthalactone C], a natural product iso-lated from the whole plant Sieb., is a typical lin-den-ane-type sesquiterpenoid. The mol-ecule com-prises a bi-cyclo-[3.1.0]hexane ring (/ system) bearing an acetoxymethyl (C-4) group, a bi-cyclo-[4.3.0]nonane ring (/ 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 cyclo-hexan-8-ene ( ring). In the tetra-cyclic skeleton, the 1,3-cyclo-propane ring has a β-con-figuration, and atoms H-5 and H-14 have α- and β-orientations, respectively. In the crystal, the mol-ecules are assembled into a two-dimensional network by weak O⋯H/H⋯O inter-actions. 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.