A systematic methodology is developed for the synthesis of highly symmetric, polysubstituted cubanes. The synthesis of cubanes with Cj" and T¡¡ symmetry is achieved. Details are given for the preparation of 1,3,5-trinitrocubane and 1,3,5,7-tetranitrocubane, compounds of interest as superior high-energy, shock-insensitive explosives. The structures of these new materials, determined by single-crystal X-ray analysis, are discussed in detail. DSC analysis of their thermal decomposition is presented. The effect of nitro groups on the 13C-NMR spectra of cubanes is noted.Nitrocubanes are sought after as powerful, shock-insensitive, high-density explosives.* 1 1,3-and 1,4-dinitrocubanes are already known.2•3 These are stable compounds with decomposition points above 250 °C. Neither shows evidence of shock sensitivity under ordinary conditions. These nitrocubanes are (now) simply made However, the vertical plane containing C2, C3, C6, and C7 approximates a mirror plane of symmetry. Table I. Angles (deg) between Adjacent Cube Edges" 1,3,5-Trinitrocubane C2-C1-C6 91.9(2) C1-C2-C3 88.4(2) C2-C1-C8 92.0(2) C1-C2-C5 88.9(2) C6-C1-C8 90.6(2) C3-C2-C5 88.3(2) C2-C3-C4 91.1(2) C3-C4-C5 88.3(2) C4-C3-C8 91.3(2) C3-C4-C7 88.5(2) C2-C3-C8 91.6(2) C5-C4-C7 89.1(2) C2-C5-C4 92.2(2) C5-C6-C7 88.8(2) C2-C5-C6 91.2(2) C1-C6-C7 89.5(2) C4-C5-C6 91.5(2) C1-C6-C5 87.9(2) C4-C7-C6 90.6(2) C3-C8-C7 89.4(2) C4-C7-C8 90.8(2) C1-C8-C7 89.5(2) C6-C7-C8 90.3(2) C1-C8-C3 88.0(2) 1,3,5,7-T etranitrocubane C2-C1-C6 91.1(2) C1-C2-C3 88.7(2) C2-C1-C8 91.4(2) C1-C2-C5 87.9(2) C6-C1-C8 92.0(2) C3-C2-C5 88.2(2) C2-C3-C4 91.9(2) C5-C4-C7 87.8(2) C2-C3-C8 91.3(2) C3-C4-C7 88.3(2) C4-C3-C8 91.0(2) C3-C4-C5 88.2(2) C2-C5-C4 91.7(2) C5-C6-C7 88.2(2) C2-C5-C6 91.8(2) C1-C6-C7 87.6(2) C4-C5-C6 92.6(2) C1-C6-C5 89.2(2) C4-C7-C6 91.3(2) C3-C8-C7 88.6(2) C4-C7-C8 92.1(2) C1-C8-C7 88.6(2) C6-C7-C8 91.9(2) C1-C8-C3 88.6(2)" The bond angles occurring at the odd-numbered corners of the cube, all nitro-substituted but one, are on the left and are all greater than 90°. The angles at the even-numbered corners, all hydrogen substituted, are on the right and are all less than 90°.