Crystal structure of (+)-(1S,5S,6S,7S,10S,11S,16S)-16-hy-droxy-7-(meth-oxy-meth-oxy)-11,15,18,18-tetra-methyl-3,13-dioxo-2,4-dioxa-tetra-cyclo[12.3.1.01,5.06,11]octa-dec-14-en-10-yl benzoate.

In the fused tetra-cyclic system of the title compound, C29H36O9, the five-membered dioxolane ring adopts a twist conformation; the two adjacent C atoms deviate alternately from the mean plane of the other three atoms by -0.252 (6) and 0.340 (6) Å. The cyclo-hexane, cyclo-hexene and central cyclo-octane rings show chair, half-chair and boat-chair forms, respectively. There are three intra-molecular C-H⋯O inter-actions supporting the mol-ecular conformation, with one S(6) and two S(7) graph-set motifs. In the crystal, inter-molecular O-H⋯O hydrogen bonds connect the mol-ecules into a helical chain running along the c-axis direction, generating a C(7) graph-set motif. The chains are further linked by inter-molecular C-H⋯O inter-actions to construct a three-dimensional network. There is no valid C-H⋯π inter-action. © Oishi et al. 2021.