Crystal structure of a new spiro-polytetra­hydro­furan compound with translational pseudosymmetry: rac-(2S,2′S,5′R)-2-methyl-5′-[(1R,2R,5S,5′R)-1,4,4,5′-tetra­methyl­dihydro-3′H-3,8-dioxa­spiro[bi­cyclo­[3.2.1]octane-2,2′-furan]-5′-yl]hexa­hydro[2,2′-bi­furan]-5(2H)-one

The title compound, C(22)H(34)O(6), is a product of oxidation of squalene with the catalytic system RuO(4)(cat.)/NaIO(4). The asymmetric unit contains two crystallographically independent mol­ecules of very similar geometry approximately related by the non-crystallographic translation vector c/2. As a consequence, the average diffracted intensity in the hkl layers with odd l is systematically lower than in the layers with even l. In one mol­ecule, the lactone ring and part of the adjacent tetra­hydro­furan ring are disordered over two orientations with refined occupancy ratio of 0.831 (10):0.169 (10). The crystal structure is mainly governed by van der Waals forces.