Syntheses and crystal structures of the anhydride 4-oxatetracyclo[5.3.2.02,6.08,10]dodec-11-ene-3,5-dione and the related imide 4-(4-bromophenyl)-4-azatetracyclo[5.3.2.02,6.08,10]dodec-11-ene-3,5-dione

The syntheses and crystal structures of the two title compounds, C11H10O3 (I) and C17H14BrNO2 (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) A, with C—N bond lengths of 1.393 (2) and 1.397 (2) A. 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.