5-Fluoro-3-(4-fluorophenylsulfinyl)-2-methyl-1-benzofuran

In the title compound, C15H10F2O2S, the S=O and the 4-fluorophenyl groups are located on opposite sides of the plane of benzofuran ring system, and the 4-fluorophenyl ring is nearly perpendicular to the benzofuran plane with a dihedral angle of 89.93 (4)°. In the crystal structure, molecules are linked by weak intermolecular C—H⋯O hydrogen bonding and C—H⋯π interactions.

In the title compound, C 15 H 10 F 2 O 2 S, the S O and the 4fluorophenyl groups are located on opposite sides of the plane of benzofuran ring system, and the 4-fluorophenyl ring is nearly perpendicular to the benzofuran plane with a dihedral angle of 89.93 (4) . In the crystal structure, molecules are linked by weak intermolecular C-HÁ Á ÁO hydrogen bonding and C-HÁ Á Á interactions.
The benzofuran unit is essentially planar, with a mean deviation of 0.012 (1) Å from the least-squares plane defined by the nine constituent atoms. The 4-fluorophenyl ring is almost perpendicular to the plane of the benzofuran fragment [89.93 (4)°] and is tilted slightly towards it. The crystal packing ( Fig. 2) is stabilized by weak intermolecular C-H···O hydrogen bonds; the first one between the methyl H atom and the oxygen of the S═O unit, with a C9-H9B···O2 i , and the second one between the 4-fluorophenyl H atom and the oxygen of the S═O unit, with a C14-H14···O2 ii , respectively (Table 1). The molecular packing ( Fig. 2) is further stabilized by a C-H···π interaction between the 4-fluorophenyl H atom and the furan ring of an adjacent benzofuran system, with a C15-H15···Cg ii (Table 1; Cg is the centroid of the C1/C2/C7/O1/C8 furan ring).

Experimental
77% 3-Chloroperoxybenzoic acid (291 mg, 1.3 mmol) was added in small portions to a stirred solution of 5-fluoro-3-(4fluorophenylsulfanyl)-2-methyl-1-benzofuran (350 mg, 1.2 mmol) in dichloromethane (30 ml) at 273 K. After being stirred at room temperature for 4 h, the mixture was washed with saturated sodium bicarbonate solution, the organic layer was separated, dried over magnesium sulfate, filtered and concentrated at reduced pressure. The residue was purified by column chromatography (hexane-ethyl acetate, 1:1 v/v) to afford the title compound as a colorless solid [yield 78%, m.p. 418-419 K; R f = 0.49 (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 benzene at room temperature.

Refinement
All H atoms were positioned geometrically and refined using a riding model, with C-H = 0.93 Å for aryl and 0.96 Å for methyl H atoms. U iso (H) = 1.2U eq (C) for aryl and 1.5U eq (C) for methyl H atoms.
supplementary materials sup-2 Figures Fig. 1. 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.

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.