The structures of two methylated hexacyclic cage diketones, lhexacyclo
[10.2.1.0(2,11).0(4,9).0(4,14),0(9,13)]- pentadeca-5, 7-diene-3, 10-di
one, C16H14O2 and 10.2.1.0(2,11).0(4,9).0(4,14).0(9.13)]pentadeca-5, 7
-diene-3, 10-dione, C17H16O2, have been determined. All bond lengths a
nd angles are consistent with strained-cage geometry.