(Z,1S,10aR)-(-)-Menthyl 1-hy-droxy-1,2,3,5,6,7,10,10a-octa-hydro-pyrrolo-[1,2-a]azocine-10a-carboxyl-ate.

The structure determination confirms the stereochemistry of the title compound, C(21)H(35)NO(3), obtained as an inter-mediate in the enanti-oselective synthesis of de-oxy-nojirimicine analogs. The system contains a pyrrolo-[1,2-a]azocine backbone, which was synthesized by a domino process involving a [2,3]-sigmatropic rearrangement. The incorporation of a chiral auxiliary (-)-menthyl, whose stereocentres are not involved during the synthesis, enables the assignation of absolute configuration. The crystal structure features O-H⋯O hydrogen bonds involving the hy-droxy groups as donors and the carbonyl groups as acceptors, which link the mol-ecules into chains running along [010].