Crystal structure and Hirshfeld surface analysis of (RS)-3-hydroxy-2-{[(3aRS,6RS,7aRS)-2-(4-methylphenylsulfonyl)-2,3,3a,6,7,7a-hexahydro-3a,6-epoxy-1H-isoindol-6-yl]methyl}isoindolin-1-one

The title compound crystallizes with two independent molecules in the asymmetric unit. In the crystal, strong intermolecular O—H⋯O hydrogen bonds and weak intermolecular C—H⋯O contacts link the molecules, forming a three-dimensional network. In addition, weak π–π stacking interactions are observed.

The title compound, C 24 H 24 N 2 O 5 S, crystallizes with two independent molecules (A and B) in the asymmetric unit. In the central ring systems of both molecules, the tetrahydrofuran rings adopt envelope conformations, the pyrrolidine rings adopt a twisted-envelope conformation and the six-membered ring is in a boat conformation. In molecules A and B, the nine-membered groups attached to the central ring system are essentially planar (r.m.s. deviations of 0.002 and 0.003 Å , respectively). They form dihedral angles of 64.97 (9) and 56.06 (10) , respectively, with the phenyl rings. In the crystal, strong intermolecular O-HÁ Á ÁO hydrogen bonds and weak intermolecular C-HÁ Á ÁO contacts link the molecules, forming a three-dimensional network. In addition weakstacking interactions [centroid-to centroid distance = 3.7124 (13) Å ] between the pyrrolidine rings of the nine-membered groups of A molecules are observed. Hirshfeld surface analysis and two-dimensional fingerprint plots were used to quantify the intermolecular interactions present in the crystal, indicating that the environments of the two molecules are very similar. The most important contributions for the crystal packing are from HÁ Á ÁH (55.8% for molecule A and 53.5% for molecule B), OÁ Á ÁH/HÁ Á ÁO (24.5% for molecule A and 26.3% for molecule B) and CÁ Á ÁH/HÁ Á ÁC (12.6% for molecule A and 15.7% for molecule B) interactions.

Chemical context
Currently, considerable attention is being paid to the development of atom-and step-economic tools in order to obtain new, practically useful materials. Tandem and domino reactions play an important role in this arsenal, since the isolation of intermediates is not required in these processes, as all reaction steps occur spontaneously (Tietze & Beifuss, 1993).
The reaction proceeds smoothly in boiling water. Separation and subsequent crystallization of the resulting solids from ethyl acetate provides the title adduct 3 in moderate yield. The process starts with the Hinsberg N-sulfonylation of amine 1, leading to the formation of the intermediate N-sulfonamide (2), which undergoes spontaneous intramolecular Diels-Alder reaction. It should be noted that the exo-[4 + 2] cycloaddition proceeds stereoselectively with the exclusive formation of diastereoisomer 3 (Fig. 1).

Supramolecular features
In the crystal, strong intermolecular O-HÁ Á ÁO hydrogen bonds and weak intermolecular C-HÁ Á ÁO contacts link the molecules, forming a three-dimensional network (  View of the two independent molecules, A and B, in the asymmetric unit of the title compound 3, with displacement ellipsoids for the nonhydrogen atoms drawn at the 30% probability level.

Figure 3
Overlay image of the two molecules (A and B) in the asymmetric unit of the title compound 3.

Hirshfeld surface analysis
The Hirshfeld surfaces for both independent molecules (A and B) in the asymmetric of the title compound 3 were generated using Crystal Explorer 17 (Turner et al., 2017). The d norm mappings were performed in the range of À0.6446 to 1.7383 arbitrary units for the molecule A and À0.5749 to 1.6904 arbitrary units for molecule B. Bold red circles on the d norm surfaces (Fig. 5a) indicate regions of O-HÁ Á ÁO interactions. The C-HÁ Á ÁO interactions also cause red spots on the Hirshfeld surfaces. The shape-index maps (Fig. 5b) contain red and blue triangles related tointeractions.

Figure 4
A view of the intermolecular C-HÁ Á ÁO and O-HÁ Á ÁO interactions in the crystal structure of the title compound 3.

Figure 5
(a) View of the three-dimensional Hirshfeld surfaces for molecules A and B of the title compound 3; (b) Hirshfeld surfaces plotted over shapeindex.

Table 2
Summary of short interatomic contacts (Å ) in the title compound 3.

Contact Distance
Symmetry operation gives the contributions of the other, less significant contacts. As shown in Table 3, the environments of the two molecules A and B are very similar. Even the packing looks pseudomonoclinic, with a pseudo-glide plane relating the two molecules A and B.
In the crystal of ERIVIL, weak intermolecular C-HÁ Á ÁO hydrogen bonds link the molecules into R 2 2 (8) and R 2 2 (14) rings along the b-axis direction. In the crystal of AGONUH, C-HÁ Á ÁO hydrogen bonds link the molecules into zigzag chains running along the b-axis direction. In the crystal of TIJMIK, two types of C-HÁ Á ÁO hydrogen bonds generate R 2 2 (20) and R 4 4 (26) rings, with adjacent rings running parallel to the ac plane. Further C-HÁ Á ÁO hydrogen bonds form a C(6) chain, linking the molecules in the b-axis direction. In the crystal of UPAQEI, molecules are linked by C-HÁ Á ÁO hydrogen bonds. In the crystal of YAXCIL, C-HÁ Á ÁO hydrogen bonds link the molecules into a three-dimensional network. In the crystal of MIGTIG, the molecules are linked only by weak van der Waals interactions. The compound BILLAL contains two molecules in the asymmetric unit, which are hydrogen-bonded dimers. The bonds closest to linearity are between the carbonyl groups and the amine H atoms. Intermolecular hydrogen bonding involving the O atoms also occurs.

Refinement details
Crystal data, data collection and structure refinement details are summarized in Table 4. The hydrogen atoms of the hydroxy groups were located in a difference-Fourier map and refined freely. The other hydrogen atoms were constrained to ride on their parent atoms with C-H = 0.95, 0.98, 0.99 and 1.00 Å for aromatic, methyl, methylene and methine H atoms, respectively. Isotropic displacement parameters of these atoms were constrained to 1.5U eq (C) for the methyl and to 1.2U eq (C) for all other H atoms.   program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL (Sheldrick, 2015b); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: PLATON (Spek, 2020). 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.