(1S,3R,8S,9S,10R)-2,2-Dichloro-9,10-epoxy-3,7,7,10-tetramethyltricyclo[6.4.0.0(1,3)]dodecane and (1S,3R,8S,10R)-2,2-dichloro-3,7,7,10-tetramethyltricyclo[6.4.0.0(1,3)]dodecan-9-one.

The stereochemistries of the title compounds, both C(16)H(24)Cl(2)O, have been established by X-ray diffraction. In both structures, the seven-membered ring adopts the same conformation, whereas the six-membered ring shows an envelope conformation in the epoxydodecane structure and a boat conformation in the dodecan-9-one structure.