2-Tosyl-2,3,3a,4,9,9a-hexahydro-1H-benzo[f]isoindol-1-one

The title compound, C19H19NO3S, was produced by the self-reaction of N-cinnamyl-N-tosylacrylamide in the presence of palladium(II) acetate via an intramolecular C—C coupling reaction and C—H activation. There are two chiral C atoms in the molecule, but the crystal is a racemic system due to a lack of chiral separation. The five-membered ring is twisted about the methylene–methane bond, and the cyclohexa-1,4-diene ring has a boat conformation. The dihedral angle between the benzene rings is 88.27 (14)°, indicating an almost orthogonal relationship and an approximate L-shape for the molecule. In the crystal, the presence of C—H⋯π interactions leads to inversion dimers.

Cg1 is the centroid of the C1-C6 ring.
We thank the National Science Foundation of China (project Nos. 21272005 and 21072003) for financial support for this work.
The crystal structure data of molecule (I), C 19 H 19 NO 3 S, reveals that all the bond lengths and angles have normal values.
An asymmetric unit is composed of one title compound molecule. The title compound molecule contains two phenyl ring, one five-member carbon ring, and one six-member carbon ring. All the rings are not coplanar (figure 1). In the molecule (I) there are two chiral carbon atoms, C8 and C9, but the crystal is a racemic system due to lacking of the chiral separation. The five-membered ring is twisted about the methylene-methane bond, and the cyclohexa-1,4-diene ring has a boat conformation. The dihedral angle between the benzene rings is 88.27 (14)°, indicating an almost orthogonal relationship and an approximate L-shape for the molecule. In the crystal, the presence of C-H···π interactions leads to inversion dimers. The molecules with R, S(C8, C9) conformation form a 1-D chain through weak H9···O 1 i (i: 1 + x, y,z) interactions, so do molecules with S, R(C8 iii , C9 iii ) conformation (H9 iii ···O 1 iv (iii: -x, 1 -y,1 -z; iv: 1 -x,1 -y,1 -z). Two chains are parallel with each other along the a axis( Fig. 2).

Experimental
An oven-dried Schlenk flask was evacuated, filled with nitrogen, and then charged with N-cinnamyl-N-tosylacrylamide (3.41 g, 10 mmol), tributylamine (3 ml), PPh 3 (52.5 mg, 0.2 mmol), Pd(OAc) 2 (24 mg, 0.1 mol), and DMF (10 ml) to give a yellow solution. The reaction mixture was heated at 393 K with stirring. The reaction mixture was cooled to room temperature after 16 h and the resultant yellow-orange mixture was diluted with Et 2 O (10 ml). The mixture was washed with H 2 O (15 ml) and the aqueous layer was extracted with Et 2 O (20 ml). The combined organic layers were dried (MgSO 4 ), filtered, and concentrated in vacuo. The crude material was purified by flash column chromatography on silica gel (petroleum ester:EtOAc = 7:1) and recrystalized from EtOAc, yield 3.11 g (91%). Colorless crystals suitable for Xray diffraction were obtained by recrystallization from a solution of the title compound from ethyl acetate over a period of one week.

Refinement
H atoms were positioned geometrically and refined using a riding model with C-H = 0.93-0.97 Å, and with U iso (H) = 1.2 times U eq (C).

Figure 1
A view of the title compound showing the atom-numbering scheme and displacement ellipsoids drawn at 30% probability level.

Special details
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'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 > σ(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.