5-Cyclopentyl-2-methyl-3-(3-methylphenylsulfonyl)-1-benzofuran

In the title compound, C21H22O3S, the five-membered ring adopts an envelope conformation with the ipso atom deviating by 0.596 (2) Å from the plane through the rest of the ring atoms. The dihedral angle between the mean planes of the benzofuran and m-tolyl moieties is 78.4 (1)°. In the crystal, molecules related by a glide plane are linked via C—H⋯O hydrogen bonds into chains along the a-axis direction. These chains are in turn connected by C—H⋯π interactions into layers parallel to the ac plane.

Supporting information for this paper is available from the IUCr electronic archives (Reference: LD2123).

Comment
As a part of our ongoing study of 5-cyclopentyl-2-methyl-1-benzofuran derivatives containing phenylsulfonyl (Seo et al., 2011) and 4-bromophenylsulfonyl (Choi et al., 2012) substituents in the 3-position, we report here on the crystal structure of the title compound.
In the title molecule ( Fig. 1), the benzofuran ring system is essentially planar, with a mean deviation of 0.015 (2) Å from the least-squares plane defined by the nine constituent atoms. The 3-methylphenyl ring is essentially planar, with a mean deviation of 0.008 (2) Å from the least-squares plane defined by the six constituent atoms. The cyclopentyl ring has an envelope conformation. The dihedral angle formed by the benzofuran ring system and the 3-methylphenyl ring is 78.44 (8)°.
In the crystal structure (Fig. 2), the molecules are linked by C-H···O hydrogen bonds (Table 1) related by gliding plane a perpendicular to b-axis. The chains of C-H···O bonded molecules are stacked by C-H···π interactions (Table 1, Cg1 is the centroid of the C15-C20 3-methylphenyl-ring), resulting in a two-dimensional supramolecular layers.
After being stirred at room temperature for 10h, 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 (benzene) to afford the title compound as a colorless solid [yield 73%, m.p. 417-418 K; R f = 0.48 (benzene)]. Single crystals suitable for X-ray diffraction were prepared by slow evaporation of a solution of the title compound in acetone 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 0.98 Å for methyl H atoms, respectively. 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 using the SHELXL-97's command AFIX 137 (Sheldrick, 2008).  The molecular structure of the title molecule with the atom numbering scheme The displacement ellipsoids are drawn at the 50% probability level. The hydrogen atoms are presented as small spheres of arbitrary radius.

Figure 2
A view of the C-H···O and C-H···π interactions (dotted lines) in the crystal structure of the title compound. H atoms non-participating in hydrogen-bonding were omitted for clarity. [Symmetry codes: (i) x + 1/2, -y + 1/2, z; (ii) x, y + 1, z; where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.54 e Å −3 Δρ min = −0.24 e Å −3 Absolute structure: Flack (1983), 1205 Friedel pairs Absolute structure parameter: 0.00 (9) 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq S1 0.04477 (