3-(4-Fluorophenylsulfonyl)-2,5,7-trimethyl-1-benzofuran

In the title compound, C17H15FO3S, the 4-fluorophenyl ring makes a dihedral angle of 72.67 (5)° with the benzofuran plane. In the crystal, molecules are linked by weak intermolecular C—H⋯O hydrogen bonds.

In the title compound, C 17 H 15 FO 3 S, the 4-fluorophenyl ring makes a dihedral angle of 72.67 (5) with the benzofuran plane. In the crystal, molecules are linked by weak intermolecular C-HÁ Á ÁO hydrogen bonds.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: DS2040).
The benzofuran unit is essentially planar, with a mean deviation of 0.009 (1) Å from the least-squares plane defined by the nine constituent atoms. The 4-fluorophenyl ring makes a dihedral angle of 72.67 (5)° with the benzofuran plane. The crystal packing (Fig. 2) is stabilized by three intermolecular C-H···O hydrogen bonds; the first one between the methyl H atom and the oxygen of the O═S═O unit, with a C10-H10B···O2 i , the second one between the 4-fluorophenyl H atom and the oxygen of the O═S═O unit, with a C13-H13···O2 ii , and the third one between the 4-fluorophenyl H atom and the oxygen of the O═S═O unit, with a C17-H17···O3 iii , respectively (Table 1).

Experimental
77% 3-Chloroperoxybenzoic acid (538 mg, 2.4 mmol) was added in small portions to a stirred solution of 3-(4-fluorophenylsulfanyl)-2,5,7-trimethy-1-benzofuran (343 mg, 1.2 mmol) in dichloromethane (50 mL) at 273 K. After being stirred at room temperature for 8h, the mixture was washed with saturated sodium bicarbonate solution and the organic layer was separated, dried over magnesium sulfate, filtered and concentrated at reduced pressure. The residue was purified by column chromatography (silica gel, hexane-ethyl acetate, 2:1 v/v) to afford the title compound as a colorless solid [yield 79%, m.p. 414-415 K; R f = 0.41 (benzene)]. 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.

Refinement
All H atoms were positioned geometrically and refined using a riding model, with C-H = 0.95 Å for aryl and 0.98 Å for methyl H atoms, U iso (H) = 1.2 U eq (C) for aryl and 1.5U eq (C) for methyl H atoms.

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 0.48710 (5)