4,4-Dimethyl-2-tosyl-1,2,3,3a,4,11b-hexa-hydro-11H-pyrrolo[3,4-c]pyrano[5,6-c]chromen-11-one 0.125-hydrate.

In the title compound, C23H23NO5S·0.125H2O, the pyrrolidine ring has a twist conformation and the dihydro­pyran ring adopts a half-chair conformation; the two rings are cis-fused. The mol­ecule adopts a folded conformation. The sulfonyl-bound phenyl ring and the pyran ring of the coumarin ring system are stacked over one another, with a centroid–centroid distance of 3.7470 (7) A; the dihedral angle between the two rings is 18.93 (2)°. An intra­molecular C—H⋯O hydrogen bond is observed. The solvent water mol­ecule, lying on a twofold rotation axis, is only partially occupied with an occupancy of 0.125 (relative occupancy with respect to the main molecule) and is involved in O—H⋯O and C—H⋯O hydrogen bonding.