(1SR,3RS,3aSR,6aRS)-Methyl 5-methyl-4,6-dioxo-3-[2-(trifluoro-meth-yl)phen-yl]octa-hydro-pyrrolo-[3,4-c]pyrrole-1-carboxyl-ate.

In the title compound, C(16)H(15)F(3)N(2)O(4), the relative stereochemistry of the four stereogenic C atoms has been determined. The carb-oxy-methyl and 2-(trifluoro-meth-yl)-phenyl substituents of the pyrrolidine cycle have a cis mutual arrangement. The five-membered saturated aza-cycle adopts an envelope conformation with the N atom occupying the flap position. In the crystal, adjacent mol-ecules are combined in centrosymmetric dimers by two weak N-H⋯O hydrogen bonds.