Ethyl 1-benzyl-1,2,3,3a,4,10b-hexa-hydro-pyrrolo-[2',3':3,4]pyrrolo-[1,2-a]benzimidazole-2-carboxyl-ate.

The title mol-ecule, C(22)H(23)N(3)O(2), was obtained via an intra-molecular cyclo-addition of an azomethine ylide and an alkene tethered by a benzimidazole unit. The benzoimidazole unit is essentially planar, with an r.m.s. deviation of 0.0087 Å from the nine constituent atoms. It has a cis fusion of the two pyrrolidine rings as well as a cis ester appendage. The two pyrrolidine rings rings have envelope conformations. The crystal packing is stabilized by aromatic π-π stacking of parallel benzimidazole ring systems, with a centroid-to-centroid distance of 3.518 (6) Å. Weak inter-molecular C-H⋯O contacts may also play a role in the stability of the packing.