(2S,3R,4R,5R)-3,4-Dihydr-oxy-5-(hydroxy-meth-yl)pyrrolidine-2-carboxylic acid [(2S,3R,4R,5R)-3,4-dihydr-oxy-5-(hydroxy-meth-yl)proline].

The crystal structure of the title compound, C(6)H(11)NO(5), establishes the relative configuration at the four stereogenic centres; the absolute configuration is determined by the use of d-glucuronolactone as the starting material for the synthesis. Mol-ecules are linked by inter-molecular O-H⋯O and N-H⋯O hydrogen bonds into a three-dimensional network, with each mol-ecule acting as a donor and acceptor for five hydrogen bonds.