5-Chloro-2-phenyl-3-phenylsulfinyl-1-benzofuran

In the title compound, C20H13ClO2S, the O atom and the phenyl group of the phenylsulfinyl substituent lie on opposite sides of the plane of the benzofuran fragment; the S-bound phenyl ring is nearly perpendicular to this plane [80.87 (5)°]. The phenyl ring in the 2-position is rotated out of the benzofuran plane, making a dihedral angle of 17.43 (7)°. The crystal structure features π–π interactions between the phenyl ring and the furyl ring of a neighbouring benzofuran system [centroid–centroid distance = 3.886 (2) Å].

In the title compound, C 20 H 13 ClO 2 S, the O atom and the phenyl group of the phenylsulfinyl substituent lie on opposite sides of the plane of the benzofuran fragment; the S-bound phenyl ring is nearly perpendicular to this plane [80.87 (5) ]. The phenyl ring in the 2-position is rotated out of the benzofuran plane, making a dihedral angle of 17.43 (7) . The crystal structure featuresinteractions between the phenyl ring and the furyl ring of a neighbouring benzofuran system [centroid-centroid distance = 3.886 (2) Å ].
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 dihedral angle in (I) formed by the plane of the benzofuran ring and the plane of 2-phenyl ring is 17.43 (7)°, and the phenyl ring (C15-C20) with80.87 (5) ° lies toward the benzofuran plane. The crystal packing ( Fig. 2) is stabilized by aromatic π-π interactions between the benzene ring and the furan ring from the neighbouring bennzofuran systems. The Cg1···Cg2 i distance is 3.886 (2) Å (Cg1 and Cg2 are the centroides of the C2-C7 benzene ring and the C1/C2/C7/O1/C8 furan ring, respectively).

Experimental
The 77% 3-chloroperoxybenzoic acid (157 mg, 0.7 mmol) was added in small portions to a stirred solution of 5-chloro-2phenyl-3-phenylsulfanyl-1-benzofuran (226 mg, 0.7 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, 2:1 v/v) to afford the title compound as a colorless solid [yield 76%, m.p. 421-422 K; R f = 0.55 (hexane-ethyl acetate, 2:1 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 aromatic H atoms and with U iso (H) = 1.2U eq (C) for aromatic 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.