CRYSTAL AND MOLECULAR-STRUCTURE OF 8-EPI-9-EPI-FURANDIOL, AN UNUSUAL TRANS-FUSED LACTARANE SESQUITERPENE

The crystal and molecular structure of 8-epi-9-epi-furandiol (3) has b een determined on the basis of X-ray diffraction data. The crystals ar e orthorhombic, space group P2(1)2(1)2(1). Z = 4; cell constants: a = 6.931(2), b = 14.050(3), c = 14.419(3) angstrom. The structure was sol ved by direct methods and refined by a full-matrix, least-squares proc edure on 1659 observed reflections. giving R = 0.0497 and R(w) = 0.038 8 (w = 1.126/sigma(F)2). The occurence of the trans-fused lactarane in 3 was confirmed by consideration of the 7-membered ring conformation. A complicated hydrogen bonding scheme involving the hydroxyl groups a s well as the crystalline water molecule was found in the crystal latt ice.