Syntheses and crystal structures of the anhydride 4-oxa­tetra­cyclo­[5.3.2.0(2,6).0(8,10)]dodec-11-ene-3,5-dione and the related imide 4-(4-bromo­phen­yl)-4-aza­tetra­cyclo­[5.3.2.0(2,6).0(8,10)]dodec-11-ene-3,5-dione

The syntheses and crystal structures of the two title compounds, C(11)H(10)O(3) (I) and C(17)H(14)BrNO(2) (II), both containing the bi­cyclo­[2.2.2]octene ring system, are reported here [the structure of I has been reported previously: White & Goh (2014 ▸). Private Communication (refcode HOKRIK). CCDC, Cambridge, England]. The bond lengths and angles of the bi­cyclo­[2.2.2]octene ring system are similar for both structures. The imide functional group of II features carbonyl C=O bond lengths of 1.209 (2) and 1.210 (2) Å, with C—N bond lengths of 1.393 (2) and 1.397 (2) Å. The five-membered imide ring is nearly planar, and it is positioned exo relative to the alkene bridgehead carbon atoms of the bi­cyclo­[2.2.2]octene ring system. Non-covalent inter­actions present in the crystal structure of II include a number of C—H⋯O inter­actions. The extended structure of II also features C—H⋯O hydrogen bonds as well as C—H⋯π and lone pair–π inter­actions, which combine together to create supra­molecular sheets.