Crystal structure of (1S,2R,4S)-1-[(morpholin-4-yl)methyl]-4-(prop-1-en-2-yl)cyclohexane-1,2-diol

Besides intramolecular O—H⋯N hydrogen bonds, the crystal structure displays intermolecular O—H⋯O and C—H⋯O hydrogen bonds linking the molecules into undulating layers parallel to the (01) plane.


Chemical context
1,2-Aminoalcohols are important building blocks in the synthesis of natural products, pharmaceuticals and other materials (Mö ller, 1957). The classical synthetic approach towards aminoalcohols involves aminolysis of epoxides with an excess of amines. There are some limitations to this classical approach, such as the requirement of elevated reaction temperatures in the case of less reactive amines, lower reactivity for sterically crowded amines/epoxides, and poor regioselectivity of the epoxide ring opening (Sello et al., 2006). To obviate these problems, various methodologies to undertake epoxide opening under milder conditions have been developed (Surendra et al., 2005), but there are still many limitations, such as the formation of bisalkylated products, longer reaction times, stoichiometric amounts of catalysts and harsh reaction conditions.
Recently, we have shown that calcium(II) compounds are very useful, environmentally friendly catalysts for several acid-catalysed reactions (Harrad et al., 2010). Moreover, calcium triflate works under almost neutral conditions. In a continuation of our ongoing program on the aminolysis of 1,2epoxides using a mild, practical and efficient method under solvent-free conditions Outouch, Boualy, El Firdoussi et al., 2011;Outouch et al., 2014), we report herein the synthesis and crystal structure of a new aminodiol from epoxyperillyl alcohol, which can be used as a chiral ligand for catalytic enantioselective transformations. The title compound was prepared by condensation of epoxyperillyl alcohol with morpholine using a catalytic amount of Ca(CF 3 COO) 2 under solvent-free conditions according to the procedure described previously (

Structural commentary
As shown in Fig. 1, there are two molecules in the asymmetric unit of the title compound. In both molecules, the cyclohexane rings adopt a chair conformation, with atoms C1/C4 and C15/ C18 as flaps. The hydroxyl groups are all in axial positions. A chair conformation is also observed for the morpholine rings, with the N and O atoms as flaps. The molecular conformation is enforced by an intramolecular O-HÁ Á ÁN hydrogen bond (Table 1).

Supramolecular features
In the crystal, molecules are linked by O-HÁ Á ÁO hydrogen bonds (Table 1) involving the hydroxyl groups into chains running parallel to the [101] direction (Fig. 2). Moreover, the chains are further connected via C-HÁ Á ÁO hydrogen bonds, forming undulating layers parallel to the (101) plane.

Figure 2
A packing diagram of the title compound showing hydrogen bonds as dashed lines (see Table 1 for details).

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 2. The H atoms attached to oxygen could be found in a difference Fourier map and were freely refined. All other H atoms were placed in idealized positions with d(C-H) = 0.95-0.99 Å and refined using a riding model, with U iso (H) = 1.2 U eq (C) or 1.5 U eq (C) for methyl H atoms. A rotating model was adopted for the methyl groups. The absolute configuration was not established by anomalous scattering effects, the enantiomer was assigned by reference to an unchanging chiral center in the synthetic procedure.   program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).