Ethyl 1 '-methyl-2-oxo-4 '-[(3aR,5R,5aS,8aS,8bR)-2,2,7,7-tetramethyltetrahydro-3aH-bis[1,3]dioxolo[4,5-b:4 ',5 '-d]pyran-5-yl]-2H-spiro[acenaphthylene1,2 '-pyrrolidine]-3 '-carboxylate

In the title molecule, C30H35NO8, the acenaphthylenone moiety, two atoms of a methyl pyrrolidine ring (N and C atoms) and four atoms of an ethyl acetate moiety (two C and two O atoms) are disordered over two sets of sites in ratio 0.532 (7): 0.468 (7). The three C atoms of a dimethoxyethane ring and dioxolane ring attached with two methyl groups are disordered over two sets of sites in 0.66 (2): 0.34 (2) and 0.62 (2): 0.38 (2) ratios, respectively. The major and minor components of the acenaphthylene ring are essentially planar(r.m.s. deviations = 0.0254 and 0.0436 angstrom, respectively). The major and minor components of the pyrrolidine ring adopt Cenvelope conformations with C atoms displaced by 0.492 (11) and 0.595 (7) angstrom from the remaining ring atoms. One of the dioxolane rings is disordered with its major component in an envelope conformation [C displaced by 0.511 (11) angstrom] and the minor fraction is more or less planar with an r.m.s. deviation of 0.070 A angstrom. The other dioxolane ring is in an envelope conformation, with a C atom displaced by 0.438 (3) angstrom from the remainder of the ring atoms. The crystal packing features C-H center dot center dot center dot O interactions, which generate C(9) chains.