MICHELIOLIDE

C15H20O3, M(r) = 248.3, orthorhombic, C222(1), a = 7.5919 (7), b = 15.5508 (7), c = 22.349 (3) angstrom, V = 2638.5 (7) angstrom 3, Z = 8, D(x) = 1.250 Mg m-3, lambda(Cu K-alpha) = 1.54184 angstrom, mu = 0.65 mm-1, F(000) = 1072, T = 294 K, R = 0.030 for 1488 observations with I > 3-sigma(I) (of 1544 unique data). The seven-membered ring is trans fused to the lactone ring. The two five-membered rings are in half-chair conformations while the seven-membered ring is in a distorted-chair conformation, with the pseudomirror bisecting the double bond. The C14 methyl group is disordered into two rotamers. Molecules form weakly hydrogen-bonded dimers about twofold axes, in which the OH H atom is disordered. The hydroxy group donates an intermolecular bifurcated hydrogen bond to both O atoms of the lactone ring [O...O (carbonyl) 3.399 (2), O...O (ring) 3.131 (2) angstrom] and accepts a second hydrogen bond from the hydroxy group of the same molecule [O...O 3.004 (2) angstrom].