Experimental

R factor = 0.039; wR factor = 0.096; data-to-parameter ratio = 8.5. In the title compound, C18H22O4, the cyclohexane and cyclohexanone rings adopt normal chair and half-chair conformations, respectively. The dioxolane ring is almost planar, with an r.m.s. deviation of 0.094 (3) Å. In the crystal, molecules are connected by O—H O hydrogen bonds, forming 21 helical chains along the a-axis direction. The chains are further connected by C—H O hydrogen bonds. Related literature For related structures having condensed cyclohexanone rings, see: Li et al. (2002); Lopez-Alvarado et al. (2002). For a related structure with a cyclohexanone ring, see: Shallard-Brown et al. (2005). For the synthesis, see: Tomizawa et al. (2009)