Crystal structure of (5R)-5-[(1S)-1,2-dihydroxyethyl]-4-methoxy-3-phenyl-2,5-dihydrofuran-2-one

In the title compound, C13H14O5, the furan ring is essentially planar [maximum deviation = 0.031 (3) Å] with a stereogenic center (R) at the sp 3 hybridized C atom. The C atom bearing the dihydroxy ethyl group is S. The absolute configuration is based on the precursor in the synthesis. The two O—H groups are in an anti conformation with respect to each other. The mean plane of the furanone group is twisted by 8.2 (4)° from that of the phenyl ring. In the crystal, molecules are linked by O—H⋯O hydrogen bonds involving furanone C=O groups and symmetry-related hydroxy groups, forming a two-dimensional network parallel to (001). Weak C—H⋯O hydrogen bonds are observed within the two-dimensional network.

In the title compound (  Table 1) to form a two-dimensional network paralllel to (001).
Weak C-H···O hydrogen bonds are observed within the two-dimensional network.

S2. Experimental
Referring to Fig. 1, to a solution of (R)-5-((S)-2,2-dimethyl-1,3-dioxolan-4-yl)-4-methoxy-3-phenylfuran-2-(5H)-one (0.570 g) in 5.0 mL THF was added 2.00 mL of 20% H 2 SO 4 at room temperature. The reaction mixture was stirred for 6 h at room temperature before it was quenched with NaHCO 3 solution. The organic layer was extracted with ethyl acetate (3 × 10 mL), combined organic layer was dried over anhydrous Na 2 SO 4 , concentrated under vacuum and eluted through a silica column using a mixture of hexane and ethyl acetate ( compound in a mixture of ethyl acetate and hexane.

S3. Refinement
H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms with C-H distances of 0.93-0.98 Å, O-H = 0.82Å and with U iso (H) = 1.2-1.5 U eq (C). In the absence of anomalous dispersion effects the Friedel pairs were merged before refinement. The absolute configuration is based on the precursor in the synthesis.

Figure 1
Scheme showing the synthesis of the title compound.

Figure 2
The molecular structure of (I) showing 50% probability displacement ellipsoids.

Special details
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq O1