Acta Cryst. (2003). E59, o406-o407  [ doi:10.1107/S1600536803004288 ]

()-5-Ethyl-endo-4-(4-methoxyphenyl)-2,2,anti-8-trimethyl-6-oxabicyclo[3.2.1]octan-7-one, a bicyclic -lactone

S. Xie, Y. Hou, C. Y. Meyers and P. D. Robinson

Abstract: The title bicyclic -lactone, C₁₉H₂₆O₃, (II), the thermodynamically favored lactone, was formed in the reaction of ()-cis-2,6,6-trimethyl-trans-3-ethyl-4-oxocyclohexanecarboxylic acid with p-methoxyphenylmagnesium bromide, following prolonged treatment under acidic conditions. The kinetically favored isomeric ()--lactone is described in the preceding paper [Xie et al. (2003). Acta Cryst. E, o403-o405]. In lactone (II), basically composed of an aromatic ring appended to a [3.2.1] bicyclic system, the O-C(O)-C group is asymmetric, its O-C=O angle being 120.80  (15)° and its O=C-C angle being 130.46  (16)°.

Online 7 March 2003

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