(1S,2S,5S)-2-Methyl-3-oxo-5-(prop-1-en-2-yl)cyclohexane-1-carbonitrile

The molecule of the title compound, C11H15NO, contains a cyclohexanone ring, three defined stereocenters and an exocyclic double bond. The crystal structure is the result of a study on the Michael addition reaction of (S)-carvone with sodium cyanide using ionic liquids as the reaction medium and so the absolute configuration is known from the chemistry. The six-membered ring is in a chair conformation.

The molecule of the title compound, C 11 H 15 NO, contains a cyclohexanone ring, three defined stereocenters and an exocyclic double bond. The crystal structure is the result of a study on the Michael addition reaction of (S)-carvone with sodium cyanide using ionic liquids as the reaction medium and so the absolute configuration is known from the chemistry. The six-membered ring is in a chair conformation.

Experimental
Crystal data C 11 H 15 NO M r = 177.24 Orthorhombic, P2 1 2 1 2 1 a = 5.2892 (8) (Welton, 1999, Wasserscheid andKeim, 2000). They are often preferred as being more environmentally friendly than traditional organic solvents. The range of known and available ILs has been rapidly growing and nowadays many ILs are commercially available. In accordance with current trends in academic and industrial research, in recent years our research group has also began to work towards the replacement of toxic volatile organic solvents with ILs. In the title compound, I, (Fig. 1), it is observed that the six-membered ring adopts the usual chair conformation. The C1-C2 bond of the cyclohexanone moiety adopts a cis configuration. The dihedral angle between the main plane of the cyclohexanone ring (defined for C1-C3-C4-C6) and the main plane of the lateral chain (defined for C5-C7-C8-C9) is 73.97°. The C5-C7-C8-C9 atoms of the lateral chain are co-planar but show large thermal motion. The absolute configuration was established according to the configuration of the starting material.

Experimental
Over a stirring solution of (S)-(+)-Carvone (104µL; 0.67 mmol) in the ionic liquid [TMG] [LAC] (1 mL), NaCN (39.15 mg; 0.8 mmol) was added. The mixture was stirred at 60 °C for 12 h. Then the reaction was cooled at room temperature and was quenched with water (15 mL) and extracted with AcOEt. The organic layer was washed with a aqueous solution of HCl (10%) (2x10 ml) and brine (2x10 mL), then was concentrated under vacuum and the residue was purified by flash column chromatography on silica gel (5% AcOEt/hexane) to afford the two desired diastereosiomeric compounds (116 mg; 86/14; 99%). The title compound, was crystallized using a mixture of 30% AcOEt/hexane.

Refinement
In (I) H atoms were placed in calculated positions and treated as ding atoms with C-H(tertiary), 0.98Å, C- The H atoms attached to atom C11 were located on a final difference map. Atoms C8 and C9 show large thermal motion and, as a result, their contact distances to atom C7 are shorter than would be expected. Since the C7-C8 distance was longer than the C7-C9 distance C8 was assumed to be the methyl carbon. The H atoms attached to C8 and C9 could not be clearly seen on a final difference map.
Since no atom in the structure had an atomic number greater than 8 the absolute configuration could not be deterimed with Mokα radiation hence the Flack parameter is meaningless.

Figure 1
The molecular structure of the title compound with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. 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.