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

In the title compound, C20H19FO2S, the benzofuran fragment is essentially planar, with a largest deviation from the mean plane of 0.026 (2) Å. The benzene ring makes a dihedral angle of 30.72 (12)° with this plane. The cyclopentyl group adopts an envelope conformation, with the α-C atom as the flap. This atom is disordered over two sites with occupancy factors of 0.803 (16) and 0.197 (16). In the crystal, molecules are linked by weak C—H⋯O, C—H⋯π and C—F⋯π [3.257 (3) Å] interactions.

In the title compound, C 20 H 19 FO 2 S, the benzofuran fragment is essentially planar, with a largest deviation from the mean plane of 0.026 (2) Å . The benzene ring makes a dihedral angle of 30.72 (12) with this plane. The cyclopentyl group adopts an envelope conformation, with the -C atom as the flap. This atom is disordered over two sites with occupancy factors of 0.803 (16) and 0.197 (16). In the crystal, molecules are linked by weak C-HÁ Á ÁO, C-HÁ Á Á and C-FÁ Á Á [3.257 (3) Å ] interactions.   Table 1 Hydrogen-bond geometry (Å , ).
In the title molecule ( Fig. 1), the benzofuran unit is essentially planar, with a mean deviation of 0.017 (2) Å from the least-squares plane defined by the nine constituent atoms. The cyclopentyl ring has an envelope conformation with the C10 atom as a flop. This atom is disordered over two sites, C10A and C10B, with occupancy factors of 0.803 (16) and 0.197 (16), respectively. The dihedral angle between the 3-fluorophenyl group and the mean plane of the benzofuran fragment is 30.7 (1)°. In the crystal structure, molecules are connected by weak C-H···O and C-H···π interactions (Table 1, Cg1 and Cg2 are the centroids of the C1-C3/C8/O1 furan ring and the C2-C7 benzene ring, respectively). The crystal packing (Fig. 2) also exhibits C-F···π interactions between the fluorine atom and the furan ring of an adjacent molecule, with a C16-F1···Cg1 iii distance of 3.257 (3) Å.
After being stirred at room temperature for 5h, the mixture was washed with saturated sodium hydrocarbonate 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, 1:2 v/v) to afford the title compound as a colorless solid [yield 81%, m.p. 430-431 K; R f = 0.56 (hexane-ethyl acetate, 1:2 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 the aryl, 1.00 Å for the methine, 0.99 Å for the methylene, and 0.98 Å for the methyl H atoms. U iso (H) = 1.2U eq (C) for the aryl, methine, and methylene H atoms, and 1.5U eq (C) for the methyl H atoms. The methyl group was allowed to rotate during the refinement.

Figure 1
The molecular structure of the title compound with the atom numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. The occupancy factors of C10A and C10B atoms are 0.803 (16)    where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 1.35 e Å −3 Δρ min = −0.55 e Å −3 Special details Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s 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.