Highly appealing alternative precursors to hetero-BCHeps would be the corresponding heteropropellanes (3-5, Fig. ). However, despite more than 50 years of research into propellane chemistry , hetero [3.1.1]propellanes have to date eluded synthesis. The physical and chemical properties of these small-ring heterocyclic propellanes are therefore entirely unchartered, and comparison with well-established carbocyclic analogues is an exciting prospect. Further, the availability of such structures would likely be of great utility in furthering the design of drug candidates, due to the diversity of bridgehead substituents that may be directly introduced during propellane ring-opening. Here we describe a general, scalable strategy for the synthesis of hetero[3.1.1]propellanes 3-5, the first members of the 'small ring' heteropropellane family to succumb to chemical synthesis. We show that these molecules can exhibit marked stability compared to their carbocyclic analogues, and are conveniently isolated without recourse to distillation as has typically been required for carbocyclic propellanes. We also disclose their ring-opening functionalisation using a variety of radical-based methods, which offers access to valuable 3-hetero-BCHeps, including the late-stage functionalisation of biologically-relevant molecules.