Structure of (+/-)-(1R*,4S*,6S*)-1-benzyloxy-4,8,11,11-tetramethyl-6- phenylthio-bicyclo[5.3.1]undec-7-en-3-one.

C28H34O2S, Mr = 434.64, triclinic, P1, a = 8.9868 (7), b = 11.2933 (11), c = 12.3497 (6) A, alpha = 80.937 (6), beta = 73.108 (5), gamma = 87.405 (7) degrees, V = 1184.32 (15) A3, Z = 2, Dx = 1.22 g cm-3, mu = 1.509 cm-1, Mo K alpha radiation, lambda = 0.7107 A, F(000) = 468, T = 298 K, R = 0.0583 for 6924 reflections [Fo greater than or equal to 4 sigma(Fo)]. The cyclooctane portion of the [5.3.1] ring system is in the boat-chair conformation while the cyclohexene portion assumes the boat conformation. The carbonyl group and the alkene group are nearly parallel in the molecule with a dihedral angle of 14.9 (1) degree between planes through the two groups. Ring strain appears to cause distortion in the alkene functionality. The bond length [C7-C8 1.343 (2) A] is long for an isolated C-C double bond. The torsion angles deviate between 3.7 (2) and 18.39 (14) degrees (absolute values) from ideality. This twist in the alkene group is reflected in the non-planarity of the group [max. deviation -0.177 (2) A for C9] and in the dihedral angle between the nearly planar portions (C6,C7,C8,C11 and C7,C8,C9,C16) which is 12.1 (1) degrees.