Promising Cage-Like Energetic Compounds Based on Dioxaadamantane and Dioxaprotoadamantane Backbones: Facile Synthesis and Energetic Performance

Heteroadamantanes have a wide range of applications, so the efficient construction of their skeletons is an important issue. Herein, two all-bridged carbon-oxygenated cage-like scaffolds 2,6-dioxaadamantane-4,8,9,10-tetraol and 2,7-dioxaprotoadamantane-4,5,9,10-tetraol were constructed through a transannular O-heterocyclization strategy within only two synthetic steps, and six novel energetic materials containing four or five explosophoric groups were synthesized. The densities, oxygen balances (OBCO), and energetic properties (including detonation velocities and pressures) of all the compounds range from 1.793 to 1.939 g·cm-3, 8.33 to 13.56%, 8024 to 8701 m·s-1, and 28.25 to 35.36 GPa, respectively. All the compounds exhibit low sensitivity to both impact (>30 J) and friction (>252 N). It is noteworthy that the symmetry of the scaffolds and the position of substituents affect the physicochemical and energetic properties of the as-prepared compounds obviously. Overall, this study provides a perspective for designing and synthesizing cage-like high energy density materials (HEDMs) and explores the structure-performance relationship.