(1′S,12′R,13′S,17′S)-15′,15′-Dimethyl-1,2-dihydro-11′,14′,16′,18′-tetra­oxa-7′-aza­spiro­[indole-3,8′-penta­cyclo­[10.6.0.02,9.03,7.013,17]octa­deca­ne]-2,10′-dione

In the title compound, C22H24N2O6, the indole ring has a twist conformation and the tetra-hydro-2H-pyran-2-one ring a half-chair conformation. One of the pyrrolidine rings adopts an envelope conformation on the N atom, while the other has a twist conformation; the 'butterfly' angle between their mean planes is 62.98 (11)°. The dioxolane ring adopts a twist conformation and the tetra-hydro-furan ring has an envelope conformation on the C atom in the fused tetra-hydro-2H-pyran-2-one ring adjacent to the O atom of the tetra-hydro-furan ring. The 'butterfly' angle between the mean planes of these two five-membered rings is 69.14 (10)°. In the crystal, mol-ecules are linked by N-H⋯O hydrogen bonds, forming chains along the a axis.