MESO-1,11-DIMETHYLCYCLOTRIDECA-2,9-DIYNE-1,11-DIOL

The title compound, C15H22O2, (5), has been prepared and its structure determined. At room temperature, two conformations are observed, but at 193 K, the compound shows only the conformation which has 67% occup ancy at room temperature. The appearance of two conformations and the low symmetry of compound (5) are in accordance with the general struct ural behaviour of 13-membered-ring systems. meso-(5) crystallizes in t he monoclinic space group I2/a. The lengths of the triple bonds are cl ose to 1.175 Angstrom at room temperature and 1.188 Angstrom at 193 K. The bond angles at the triple bonds deviate by less than 7 degrees fr om being linear and are almost temperature independent.