Photochemical Strategies Enable the Synthesis of Tunable Azetidine-Based Energetic Materials

Despite their favorable properties, azetidines are often overlooked as lead compounds across multiple industries. This is often attributed to the challenging synthesis of densely functionalized azetidines in an efficient manner. In this work, we report the scalable synthesis and characterization of seven azetidines with varying regio- and stereochemistry, and their application as novel azetidine-based energetic materials, enabled by the visible light-mediated aza Paternò-Büchi reaction. The performance and stark differences in physical properties of these new compounds make them excellent potential candidates as novel solid melt-castable explosive materials, as well as potential liquid propellant plasticizers. The nitroazetidine materials synthesized exhibit reasonable sensitivities, higher densities, better oxygen balances, increased detonation pressures and velocities, as well as improved specific impulses, compared to the state-of-the-art materials. This work highlights the scalability and utility of the visible-light aza Paternò-Büchi reaction and demonstrates the impact of stereochemical considerations on the physical properties of azetidine-based energetics. Considering the versatility and efficiency of the presented synthetic strategies, we expect that this work will guide the development of new azetidine-based materials in the energetics space as well as other industries, including pharmaceuticals and agrochemicals.