(5R,8R)-2-(3,8-Dimethyl-2-oxo-1,2,4,5,6,7,8,8a-octahydroazulen-5-yl)acrylic acid (rupestonic acid)

Abstract

The title compound, C15H20O3, crystallizes with two independent molecules in the asymmetric unit. In both molecules, the seven-membered ring adopts a chair conformation. In the crystal structure, intermolecular O—H...O hydrogen bonds link the molecules into chains extending in the [201] direction. The absolute configuration was assigned on the basis of the starting materials.