5-Bromo-3-cyclohexylsulfonyl-2-methyl-1-benzofuran

In the title compound, C15H17BrO3S, the cyclohexyl ring adopts a practically undistorted chair conformation [endocyclic torsion angles are within a 54.5–56.4 (3)° range] and the arylsulfonyl unit is positioned equatorial relative to the cyclohexyl group. In the crystal, molecules are linked through C—H⋯O hydrogen bonds and donor–acceptor Br⋯O contacts [3.250 (2) Å]. The crystal structure also exhibits aromatic π–π overlap between the benzene and furan rings of neighbouring molecules [centroid–centroid distance = 3.635 (2) Å].

In the title compound, C 15 H 17 BrO 3 S, the cyclohexyl ring adopts a practically undistorted chair conformation [endocyclic torsion angles are within a 54.5-56.4 (3) range] and the arylsulfonyl unit is positioned equatorial relative to the cyclohexyl group. In the crystal, molecules are linked through C-HÁ Á ÁO hydrogen bonds and donor-acceptor BrÁ Á ÁO contacts [3.250 (2) Å ]. The crystal structure also exhibits aromaticoverlap between the benzene and furan rings of neighbouring molecules [centroid-centroid distance = 3.635 (2) Å ].
Experimental 77% 3-chloroperoxybenzoic acid (381 mg, 1.7 mmol) was added in small portions to a stirred solution of 5-bromo-3-cyclohexylsulfanyl-2-methyl-1-benzofuran (260 mg, 0.8 mmol) in dichloromethane (40 mL) at 273 K. After being stirred at room temperature for 5h, 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 (hexane-ethyl acetate, 4:1 v/v) to afford the title compound as a colorless solid [yield 76%, m.p. 446-447 K; R f = 0.58 (hexane-ethyl acetate, 4:1 v/v)]. Single crystals suitable for X-ray diffraction were prepared by slow evaporation of acetone solution of the title compound at room temperature.

Refinement
All H atoms were positioned geometrically and refined using a riding and rotating model, with C-H = 0.95 Å for aryl, 1.00 Å for methine, 0.99 Å for methylene and 0.98 Å for methyl H atoms, respectively. U iso (H) = 1.2U eq (C) for aryl, methine, methylene 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.