STRUCTURE OF A DENSELY OXYGENATED CARBOCYCLE

{3aR-[3a-alpha,4-alpha,5-beta(R*),6-alpha,6a-alpha]}-Methyl 4-{[(1,1-dimethylethyl)dimethylsilyl]oxy}tetrahydro-6-hydroxy-alpha-(1-hydroxycyclohexyl)-2,2-dimethyl-4H-cyclopenta-1,3-dioxole-5-acetate, C23H42O7Si, M(r) = 458.75, monoclinic, P2(1), a = 11.537 (2), b = 8.552 (2), c = 13.916 (4) angstrom, beta = 92.39 (2)-degrees, V = 1371.8 (5) angstrom 3, Z = 2, D(x) = 1.11 g cm-3, Mo K-alpha, lambda = 0.71069 angstrom, mu = 1.2 cm-1, F(000) = 500, T = 298 K, R = 0.0564 and wR = 0.0638 for 1475 reflections [I greater-than-or-equal-to 3-sigma(I)]. Crystal chirality was assigned to correspond to the known chirality of the precursor compound. The cyclopentane ring exhibits an envelope conformation (E1) where C(1) occupies the flap position [0.58 angstrom from the plane of C(2), C(3), C(5) and C(6)]. The dioxole ring is in an unusual planar conformation. This planarity may be partially attributed to the disorder of the C-(CH3)2 moiety at the C(4) position. The cyclohexyl ring exhibits a chair conformation (4C1) where atoms C(8) and C(11) are 0.61 angstrom and -0.66 angstrom, respectively, from the plane of atoms C(9), C(10), C(12) and C(13).