Methyl 6-deoxy-6-iodo-2,3-O-isopropylidene-α-d-mannopyranoside

In the title compound, C10H17IO5, the six-membered tetrahydropyran ring and the five-membered 1,3-dioxolane ring adopt sofa and envelope conformations, respectively. In the crystal, O—H⋯O and C—H⋯O hydrogen bonds link the molecules into layers nearly parallel to the bc plane.

In the title compound, C 10 H 17 IO 5 , the six-membered tetrahydropyran ring and the five-membered 1,3-dioxolane ring adopt sofa and envelope conformations, respectively. In the crystal, O-HÁ Á ÁO and C-HÁ Á ÁO hydrogen bonds link the molecules into layers nearly parallel to the bc plane.
In the crystal structure, intermolecular O-H···O and C-H···O hydrogen bonds (Table 1) link the molecules into layers nearly parallel to the bc plane (Fig. 2).

Refinement
Atom H2A (for OH) was located in a difference Fourier map and refined freely. The C-bound H atoms were positioned geometrically, with C-H = 1.00, 0.99 and 0.98 Å for methine, methylene and methyl H atoms, respectively, and constrained to ride on their parent atoms, with U iso (H) = kU eq (C), where k = 1.2 for methine and methylene and k = 1.5 for methyl H atoms.

Figure 1
The molecular structure of the title compound, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.

Figure 2
A partial packing diagram. Hydrogen bonds are shown as dashed lines. H atoms not involved in hydrogen bonding have been omitted for clarity.  (12) 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 > 2sigma(F 2 ) is used only for calculating R-factors(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.