Received 13 December 2012
The chiral title compound, C19H32O2, contains a [4.3.0]-bicyclic moiety in which the shared C-C bond presents a trans configuration and a side chain in which the C=C double bond shows an E conformation. The conformations of five- and six-membered rings are envelope (with the bridgehead atom bearing the methyl substituent as the flap) and chair, respectively, with a dihedral angle of 4.08 (17)° between the idealized planes of the rings. In the crystal, the molecules are self-assembled via classical O-HO hydrogen bonds, forming chains along ; these chains are linked by weak non-classical C-HO hydrogen bonds, giving a two-dimensional supramolecular structure parallel to (010). The absolute configuration was established according to the configuration of the starting material.
The title compound is a precursor of the hormonally active form of vitamin D3. For general background to vitamin D3, see: Heaney (2008); Henry (2011). For related structures, see: Maehr & Uskokovic (2004). For puckering parameters, see: Cremer & Pople (1975).
Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1998); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009) and Mercury (Macrae et al., 2006); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: PV2614 ).
This work was supported financially by the Spanish Ministry of Foreign Affairs and Cooperation (PCIA/030052/10) and the Xunta de Galicia (INCITE845B, INCITE08PXIB314255PR).
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