(1S,3R,8S,9S,10R)‐2,2‐Dichloro‐9,10‐epoxy‐3,7,7,10‐tetramethyltricyclo[6.4.0.01,3]dodecane and (1S,3R,8S,10R)‐2,2‐dichloro‐3,7,7,10‐tetramethyltricyclo[6.4.0.01,3]dodecan‐9‐one

The stereochemistries of the title compounds, both C₁₆H₂₄Cl₂O, 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.