(3aR,6S,7aR)-7a-Chloro-2-[(4-nitrophenyl)sulfonyl]-1,2,3,6,7,7a-hexahydro-3a,6-epoxyisoindole

In the title compound, C14H13ClN2O5S, the chlorine-substituted tetrahydrofuran ring adopts a twist conformation and the other tetrahydrofuran ring an envelope conformation with the O atom as the flap. The pyrrolidine ring adopts a twist conformation. In the crystal, C—H⋯O hydrogen bonds link the molecules into zigzag chains running along the b-axis direction.

In the title compound, C 14 H 13 ClN 2 O 5 S, the chlorine-substituted tetrahydrofuran ring adopts a twist conformation and the other tetrahydrofuran ring an envelope conformation with the O atom as the flap. The pyrrolidine ring adopts a twist conformation. In the crystal, C-HÁ Á ÁO hydrogen bonds link the molecules into zigzag chains running along the b-axis direction.

Comment
The Diels Alder reaction is one of the most powerful and useful cycloaddition reactions in synthetic organic chemistry (Winkler, 1996;Paulvannan, 2004;Norton, 1942). Intra-molecular Diels Alder (IMDA) reaction should be taken into account for synthesis of a molecule containing a six membered ring fused to a second ring. The feasibility of employing IMDA has been considered the main application often becomes the preparation of the substrates in synthetic pathways (Fraile et al., 2001;Padwa et al., 2003). Thermal intramolecular Diels Alder reaction has also been popular and facile methodology since early 1980's Furan is also one of the most used diene part in thermal IMDA cycloaddition (Medimagh et al., 2008;Avalos et al., 2003).
We have been working on thermal IMDA reaction of furan cored compounds in which side chain of furan includes oxygen, sulfur and nitrogen (Karaarslan et al., 2006;Koşar et al., 2006Koşar et al., , 2007Koşar et al., , 2011Arslan et al., 2008;Temel et al., 2012). Here, we report that the new isoxazol cycloadduct, 3 in aqueous condition is furnished in one pot reaction from seconder amine, 1. We assume that the protective group on nitrogen; p-Nosyl behaves as steric buttress and accelerates the cycloaddition progress right after the protection stage, 2. The improvement of the technology and economic reaction are achieved, two processes; protection and IMDA cycloaddition stages are performed in one pot process. We consider that the improvement of this methodology will possibly allow organic chemist to a facile access to important classes of azaheterocycles ( Figure 1).
The title compound contains epoxyisoindole and phenyly rings linked through N-S-C bridge in the unit cell ( Fig. 2).
Epoxyisoindole moiety is formed with fused a six-membered ring and three five-membered rings which are puckered. Of the tetrahydrofuran rings, the one which is attached to chloride, O 5 /C 11-13 /C 8 , adopts a half-chair conformation while the other one, O 5 /C 8-11 , adopts an envelope conformation with the puckering parameters of Q=0.6011 (18)  The crystal packing of (I) is provided by inter-molecular C2-H2-O4 and C14-H14B···O5 hydrogen bonds which are generate dimeric R 2 2 (10) rings running parallel to the b axis (Bernstein et al., 1995) (Fig. 3).

Refinement
H atoms were positioned geometrically and treated using a riding model, fixing the bond lengths at 0.97, 0.98 and 0.93 Å for CH 2 , CH and CH(aromatic), respectively. The displacement parameters of the H atoms were constrained with U iso (H) = 1.2U eq (aromatic, methylene or methine C).

Computing details
Data

Figure 1
Synthesis of the title compound.

Figure 2
The molecular structure of the title compound, with displacement ellipsoids drawn at the 30% probability level.  where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.26 e Å −3 Δρ min = −0.23 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 > 2σ(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.