5-Fluoro-2-(4-fluorophenyl)-3-methylsulfinyl-1-benzofuran

In the title compound, C15H10F2O2S, the O atom and the methyl group of the methylsulfinyl substituent lie on opposite sides of the plane through the benzofuran fragment. The 4-fluorophenyl ring is rotated out of the benzofuran plane by a dihedral angle of 28.09 (3)°. The crystal structure is stabilized by weak intermolecular C—H⋯O and C—H⋯F hydrogen bonds.

In the title compound, C 15 H 10 F 2 O 2 S, the O atom and the methyl group of the methylsulfinyl substituent lie on opposite sides of the plane through the benzofuran fragment. The 4fluorophenyl ring is rotated out of the benzofuran plane by a dihedral angle of 28.09 (3) . The crystal structure is stabilized by weak intermolecular C-HÁ Á ÁO and C-HÁ Á ÁF hydrogen bonds.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: IS2465).
The benzofuran unit is essentially planar, with a mean deviation of 0.004 (1) Å from the least-squares plane defined by the nine constituent atoms. The dihedral angle formed by the plane of the benzofuran ring and the 4-fluorophenyl ring is 28.09 (3)°. The crystal packing ( Fig. 2) is stabilized by weak non-classical intermolecular C-H···O and C-H···F hydrogen bonds; the first between the 4-fluorophenyl H atom and the oxygen of the S═O unit, with a C14-H14···O2 i , the second between the methyl H atom and the fluorine of the 4-fluorophenyl ring, with a C15-H15C···F2 ii , respectively (Table 1).

S2. Experimental
77% 3-Chloroperoxybenzoic acid (359 mg, 1.6 mmol) was added in small portions to a stirred solution of 5-fluoro-2-(4fluorophenyl)-3-methylsulfanyl-1-benzofuran (414 mg, 1.5 mmol) in dichloromethane (30 mL) at 273 K. After being stirred at room temperature for 3h, the mixture was washed with saturated sodium bicarbonate solution and the organic layer was separated, dried over magnesium sulfate, filtered and concentrated in vacuum. The residue was purified by column chromatography (hexane-ethyl acetate, 1:1 v/v) to afford the title compound as a colorless solid [yield 80%, m.p. 437-438 K; Rf = 0.54 (hexane-ethyl acetate, 1:1 v/v)]. Single crystals suitable for X-ray diffraction were prepared by slow evaporation of a solution of the title compound in chloroforrm at room temperature.

S3. Refinement
All H atoms were geometrically positioned and refined using a riding model, with C-H = 0.95 Å for the aryl and 0.98 Å for the methyl H atoms, and with U iso (H) = 1.2U eq (C) for the aryl H atoms and 1.5U eq (C) for methyl H atoms.  The molecular structure of the title compound with the atom numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are presented as a small spheres of arbitrary radius. x + 1, -y + 1, -z + 1; (ii) x, y, z + 1 (iii) x, y, z -1.] 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.