Scalable Process for the Production of a Highly Energetic Bromoacetylene Building Block

3-(Bromoethynyl)­azetidine is a highly energetic building block (decomposition energy up to −1800 J g–1) that was required in multikilogram quantities for the production of an API. The development of a four-step, fully telescoped, scalable sequence for its synthesis is described, along with a detailed safety study of the corresponding hydrochloride salt in order to determine the potential explosive properties and transport classification. A screen of counterions identified the (+)-camphorsulfonic acid salt as the most suitable form for mitigation of the energetic properties, as judged by differential scanning calorimetry (onset 182 °C, energy −876 J g–1). This case study demonstrates how a daunting chemical structure can be “tamed” by chemical process development, tuning of molecular properties, and thorough safety investigations.