The title compound, C10H11NO3, crystallizes with four independent molecules in the asymmetric unit. Their geometries are very similar and corresponding bond distances are almost identical. The central six-membered ring of the indolizine moiety adopts a envelope conformation [the displacement of the flap atom (the C atom opposite the N atom) being 0.539 (2), 0.548 (3), 0.509 (3) and 0.544 (3) Å in the four molecules], while the conformation of the oxopyrrolidine ring is close to that of a flat envelope. The displacements of the non-fused C atom opposite the C=O group of the pyrrolidine ring of the four molecules are 0.366 (3), 0.335 (3), 0.173 (3) and −0.310 (3) Å. In the crystal, O—HO hydrogen bonds link the molecules into chains, which run parallel to the c axis. The absolute configuration was assigned from the synthesis.