5-Cyclohexyl-2-(2-fluorophenyl)-3-methylsulfinyl-1-benzofuran

In the title compound, C21H21FO2S, the cyclohexyl ring adopts a chair conformation. The 2-fluorobenzene ring makes a dihedral angle of 38.68 (6)° with the mean plane [r.m.s. deviation = 0.018 (2) Å] of the benzofuran fragment. In the crystal, molecules are linked by pairs of C—H⋯O hydrogen bonds into dimers, which are further packed into stacks along the c axis by C—H⋯O hydrogen bonds. In addition, the stacked molecules exhibit S⋯O contacts [3.1733 (13) Å] involving the sulfinyl groups. The F atom is disordered over two positions, with site-occupancy factors of 0.961 (3) and 0.039 (3).

In the title compound, C 21 H 21 FO 2 S, the cyclohexyl ring adopts a chair conformation. The 2-fluorobenzene ring makes a dihedral angle of 38.68 (6) with the mean plane [r.m.s. deviation = 0.018 (2) Å ] of the benzofuran fragment. In the crystal, molecules are linked by pairs of C-HÁ Á ÁO hydrogen bonds into dimers, which are further packed into stacks along the c axis by C-HÁ Á ÁO hydrogen bonds. In addition, the stacked molecules exhibit SÁ Á ÁO contacts [3.1733 (13) Å ] involving the sulfinyl groups. The F atom is disordered over two positions, with site-occupancy factors of 0.961 (3) and 0.039 (3).

Related literature
For background information and the crystal structures of related compounds, see: Choi et al. (2011Choi et al. ( , 2012. For details of sulfinyl-sulfinyl interactions, see: Choi et al. (2008). For a review of carbonyl-carbonyl interactions, see: Allen et al.  Table 1 Hydrogen-bond geometry (Å , ).
In the title molecule ( Fig. 1), the benzofuran unit is essentially planar, with a mean deviation of 0.018 (2) Å from the least-squares plane defined by the nine constituent atoms. In the 2-fluorobenzene ring, the F atom is disordered over two positions with site-occupancy factors, from refinement, of 0.961 (3) (part A) and 0.039 (3) (part B). The cyclohexyl ring has the chair form. The dihedral angle formed by the 2-fluorobenzene ring and the mean plane of the benzofuran fragment is 38.68 (6)°. In the crystal structure (Fig. 2), molecules are linked by pairs of C-H···O hydrogen bonds into centrosymmetric dimers, which are further packed into stacks along the c axis by C-H···O hydrogen bonds (Table 1). In addition, the crystal packing (Fig. 2) exhibits a sulfinyl-sulfinyl interaction (Choi et al., 2008) similar to a type-II carbonyl-carbonyl interaction (Allen et al., 1998), with a S1···O2 ii distance of 3.1733 (13) Å (symmetry operation ii: 1/2x, 1/2-y, 1-z).
After being stirred at room temperature for 5 h, 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, 2:1 v/v) to afford the title compound as a colorless solid [yield 78%, M.pt: 452-453 K; R f = 0.59 (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 ethyl acetate at room temperature.

Refinement
All H atoms were positioned geometrically and refined using a riding model, with C-H = 0.95 Å for aryl, 1.00 Å for methine, 0.99 Å for methylene and 0.98Å for methyl H atoms, respectively, and with U iso (H) = 1.2U eq (C) for aryl, methine and methylene, and 1.5U eq (C) for methyl H atoms. The positions of methyl hydrogens were optimized rotationally. The F1 atom of the 2-fluorophenyl ring is disordered over two positions with site occupancy factors, from refinement, of 0.961 (3) (part A) and 0.039 (3) (part B). For the proper treatment of H-atoms, carbon atoms C16 and C20 were divided in two parts with equalized coordinates and thermal parameters. The distance of equivalent C-F pairs were restrained to 1.330 (5) Å using command DFIX, and displacement ellipsoids of F1 set were restrained to 0.01 using command ISOR.    where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 0.36 e Å −3 Δρ min = −0.33 e Å −3 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.