Acetonide-3-trinervinone

This X-ray diffraction study establishes the molecular structure of the title compound, 2,2,4b',8',8'-pentamethyl-6,10a'-epoxyspiro[1,3-dioxepane-5,2'-perhydrophenanthren]-7'-one, C₂₃H₃₆O₄, which consists of three six-membered rings (A, B and C), and a five- and a seven-membered ring (D and E, respectively). The C ring is fused at C(8)-C(14)-C(13) to the D ring. The A/B, B/C and D/E rings are trans-, trans- and cis-fused, respectively. The A, B and C rings adopt a distorted chair ¹C₄ conformation. The D and E rings have envelope and half-chair ⁵H₄ conformations, respectively. The crystal structure is stabilized by van der Waals interactions. There are two C-H...O hydrogen bonds of less than 3.5 Å.

-1