STRUCTURE OF A COUPLED CARBOHYDRATE AND TERPENE

(1S-{1alpha,1[3R,5R*(R*)],2alpha,5beta})-5-[1, nzyloxy)ethyl]-4,5-dih ydro-3-[1-hydroxy-2-methyl-5 (1-methylvinyl)cyclohexyl]-2(3H)-furanone , C30H34O7, M(r) = 506.3, monoclinic, P2(1), a = 12.780 (1), b = 6.478 (1), c = 16.832 (2) angstrom, beta = 93.00 (1)degrees, V = 1391.6 (3) angstrom3, Z = 2, D(x) = 1.209 g cm-3, lambda(Mo Kalpha) = 0.71069 an gstrom, mu = 0.9 cm-1, F(000) = 540, T = 298 K, R = 0.0504 and wR = 0. 0584 for 2177 reflections [I greater-than-or-equal-to 2sigma(I)]. Crys tal chirality was assigned on the basis of the two components coupled to form the title compound. The carbohydrate lactone, L-gulonic-gamma- lactone, was utilized as a precursor to the tetrahydrofuran ring and t he dibenzoate appendage. In a similar manner, the terpene ketoneh(+)-d ihydrocarvone was the precursor to the cyclohexanol ring. The absolute stereochemistry of the molecule was established from the fixed C atom s C4 and C15 of the tetrahydrofuran and appendage, and C atoms C6 and C9 bearing the methyl and isopropene groups, respectively, on the cycl ohexanol ring. It is worth noting that the two rings are coupled with the least sterically hindered faces of each ring. The X-ray studies sh own herein establish the stereochemistry of the C2-O5 bond. O5-H5, the only hydroxyl group present, is involved in one intramolecular hydrog en bond with O1:O5-H5 = 0.76 (8), O5...O1 = 2.819 (5), H5...O1 = 2.28 (7) angstrom, O5-H5...O1 = 129 (7)degrees.