(3S,4S)-1-Benzylpyrrolidine-3,4-diol

In the title compound, C11H15NO2, the pyrrolidine ring adapts a twisted envelope conformation and the two hydroxyl groups are arranged in a trans conformation. The crystal packing is stabilized by intermolecular O—H⋯N and O—H⋯O hydrogen bonds. A weak C—H⋯π interaction also occurs.

In the title compound, C 11 H 15 NO 2 , the pyrrolidine ring adapts a twisted envelope conformation and the two hydroxyl groups are arranged in a trans conformation. The crystal packing is stabilized by intermolecular O-HÁ Á ÁN and O-HÁ Á ÁO hydrogen bonds. A weak C-HÁ Á Á interaction also occurs.
In the title compound, C 11 H 15 NO 2 , the pyrrolidine ring adapts a twisted envelope formation. The two hydroxyl groups at C9 and C10 are arranged in a trans-conformation. The dihedral angle between the mean planes of the pyrrolidine phenyl rings is 62.4 (2)°. Crystal packing is stabilized by intermolecular O-H···N and O-H···O hydrogen bonds interactions. A weak C-H···Cg2 π ring intermolecular intereaction is also observed, where Cg2 = C1-C6.

Experimental
The synthesis of the title compound is described by Nagel et al. (1984). Crystals were grown from its solution in acetone; m.p. 371-373 K.

Refinement
The absolute structure could not be established from the dffraction data and was assigned based on L-tartaric acid the starting material.
All the H atoms were located in difference Fourier maps. However, they were constrained by riding model approx- Fig. 1. The molecular structure of (I) showing displacement ellipsoids drawn at the 50% probability level. The hydrogen atoms are drawn as spheres of arbitrary radius.

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.