3-(4-Fluorophenylsulfinyl)-2,4,6-trimethyl-1-benzofuran

In the title compound, C17H15FO2S, the O atom and the 4-fluorophenyl group of the 4-fluorophenylsulfinyl substituent lie on opposite sides of the plane of the benzofuran; the 4-fluorophenyl ring is almost perpendicular to this plane, making a dihedral angle of 88.99 (4)°. The crystal structure exhibits intermolecular C—H⋯O hydrogen bonds and C—H⋯π interactions between the methyl H atom and the 4-fluorophenyl ring.

In the title compound, C 17 H 15 FO 2 S, the O atom and the 4fluorophenyl group of the 4-fluorophenylsulfinyl substituent lie on opposite sides of the plane of the benzofuran; the 4fluorophenyl ring is almost perpendicular to this plane, making a dihedral angle of 88.99 (4) . The crystal structure exhibits intermolecular C-HÁ Á ÁO hydrogen bonds and C-HÁ Á Á interactions between the methyl H atom and the 4fluorophenyl ring.

Experimental
Cg is the centroid of the C11-C16 ring.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: FK2013).
The benzofuran unit is essentially planar, with a mean deviation of 0.013 (2) 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 [88.99 (4)°] and is tilted slightly towards it. The crystal packing ( Fig. 2) is stabilized by an intermolecular C-H···O hydrogen bond between the methyl H atom and the oxygen of the S═O unit, with a C10-H10A···O2 i ( Table 1). The molecular packing ( Fig. 2) is further stabilized by an intermolecular C-H···π interaction between the methyl H atom and the 4-fluorophenyl ring, with a C10-H10C···Cg ii (Table 1; Cg is the centroid of the C11-C16 4-fluorophenyl ring).

Experimental
77% 3-Chloroperoxybenzoic acid (224 mg, 1.0 mmol) was added in small portions to a stirred solution of 3-(4-fluorophenylsulfanyl)-2,4,6-trimethyl-1-benzofuran (257 mg, 0.9 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 82%, m.p. 410-411 K; R f = 0.69 (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 diisopropyl ether at room temperature.

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq S 0.58051 (