2-(4-Chlorophenyl)-3-methylsulfanyl-5-phenyl-1-benzofuran

In the title compound, C21H15ClOS, the 4-chlorophenyl ring is rotated out of the benzofuran plane, making a dihedral angle of 21.50 (6)°. The dihedral angle between the 5-phenyl ring and the benzofuran plane is 29.39 (6)°. The crystal studied was an inversion twin with a 0.65 (7):0.35 (6) domain ratio.

In the title compound, C 21 H 15 ClOS, the 4-chlorophenyl ring is rotated out of the benzofuran plane, making a dihedral angle of 21.50 (6) . The dihedral angle between the 5-phenyl ring and the benzofuran plane is 29.39 (6) . The crystal studied was an inversion twin with a 0.65 (7):0.35 (6) domain ratio.

Experimental
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: FL2295).
The title compound crystallizes as the monoclinic space group P21. The crystal studied was an inversion twin with a 0.65 (7) : 0.35 (6) domain ratio. The benzofuran unit is essentially planar, with a mean deviation of 0.012 (2) Å from the least-squares plane defined by the nine constituent atoms. The dihedral angle formed by the benzofuran plane and the 4-fluorophenyl ring is 21.50 (6)°. The dihedral angle between the 5-phenyl ring and the benzofuran plane is 29.39 (6)°. No unusually close intermolecular interactions were found.

Experimental
Zinc chloride (273 mg, 2.0 mmol) was added to a stirred solution of 4-phenylphenol (340 mg, 2.0 mmol) and 2-chloro-2methylsulfanyl-4'-chloroacetophenone (470 mg, 2.0 mmol) in dichloromethane (30 ml) at room temperature, and stirring was continued at the same temperature for 40 min. The reaction was quenched by the addition of water and the organic layer separated, dried over magnesium sulfate, filtered and concentrated at reduced pressure. The residue was purified by column chromatography (carbon tetrachloride) to afford the title compound as a colorless solid [yield 51%, m.p. 420-421 K; R f = 0.63 (carbon tetrachloride)]. Single crystals suitable for X-ray diffraction were prepared by evaporation of a solution of the title compound in carbon tetrachloride at room temperature.

Refinement
The reported Flack parameter was obtained by TWIN/BASF procedure in SHELXL97-2 (Sheldrick, 2008). All H atoms were geometrically positioned 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) = 1.2U 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 supplementary materials sup-3 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.