2-Methyl-1,1-diphenyl-2-[(4S)-4-phenyl-4,5-dihydro-1,3-oxazol-2-yl]propan-1-ol

In the title compound, C25H25NO2, the phenyl ring on the 1,3-oxazole ring is disordered over two positions with occupancies of 0.600 (4) and 0.400 (4). The interplanar angle between these two disordered rings is 77.8 (2)°. There is an intramolecular O—H⋯N hydrogen bond of moderate strength. In the crystal, C—H⋯π interactions interconnect neighbouring molecules. The absolute structure has been derived from the known absolute structure of the reagents.

In the title compound, C 25 H 25 NO 2 , the phenyl ring on the 1,3oxazole ring is disordered over two positions with occupancies of 0.600 (4) and 0.400 (4). The interplanar angle between these two disordered rings is 77.8 (2) . There is an intramolecular O-HÁ Á ÁN hydrogen bond of moderate strength. In the crystal, C-HÁ Á Á interactions interconnect neighbouring molecules. The absolute structure has been derived from the known absolute structure of the reagents.

Experimental
Mono(oxazoline) (0.5 g, 2 mmol) dissolved in 10 ml of tetrahydrofuran was placed into a two-neck 50 ml round-bottom flask that had been previously dried and that was equipped with a magnetic stirrer and a nitrogen inlet. The solution was cooled to 273 K and phenylmagnesium bromide (1.4 g, 8 mmol) which had been dissolved in 2 ml of tetrahydrofuran was added dropwise under nitrogen atmosphere to the solution of monoxazoline in tetrahydrofuran. The reaction mixture was stirred for 2 h at the same temperature. Then thin layer chromatography showed that the raw material had disappeared and indicated completion of the reaction. In the following step, 15 ml of saturated NH 4 Cl was added into the reaction solution at 273 K. The product was extracted by ethyl acetate (3×10 ml). The combined ethyl acetate extracts were dried over Na 2 SO 4 . The residue obtained after the evaporation of the solvent was purified by silica gel column chromatography with petroleum ether. The crude product was dissolved in 1 ml petroleum ether and the crystals were recrystallized after 4 hours in 55% yield as white or colourless needles typically 2-3 mm long and 0.5 mm wide. Melting point: 380-381 K (determined by a X-4 digital display microscopic melting-point apparatus).

Refinement
The H atoms which have not been involved in the disordered phenyl rings were discernible in the difference electron density maps. The H atoms which were attached to the carbons were situated into the idealized positions and constrained using the following constraints: C aryl -H aryl = 0.93; C methyl -H methyl = 0.96; C methylene -H methylene = 0.97; C methine -H methine = supplementary materials sup-2 Acta Cryst. (2013). E69, o1022 0.98 Å. U iso H aryl = 1.2U eq C aryl ; U iso H methyl = 1.5U eq C methyl ; U iso H methylene = 1.2U eq C methylene ; U iso H methine = 1.2U eq C methine . The positional parameters of the hydroxyl hydrogen were freely refined while U iso H hydroxyl = 1.5U eq O hydroxyl . The occupational parameters of the disoredered phenyl rings were constrained in such a way that the their sum equalled to 1. The displacement parameters of the corresponding disordered atoms C21a, C21b ··· C25a, C25b were restrained by the command ISOR 0.01 0.02 and SIMU_* (SHELXL97, Sheldrick, 2008). In absence of significant resonant scatterers 1284 Friedel pairs have been merged by application of the command MERG 3 [SHELXL97 (Sheldrick, 2008)].

Figure 1
The title molecule with the atomic labelling scheme. The displacement ellipsoids are shown at the 50% probability level.  Packing diagram of the title molecules viewed approximately along the a axis.  (14) 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.

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