Summary. In 2022, bicyclo[3.1.1]heptanes were demonstrated to mimic the fragment of meta-substituted benzenes in biologically active compounds (Scheme 1). Here, we unexpectedly developed a general approach to their azaanalogs: 3-azabicyclo[3. 1.1]heptanes (Scheme 2). The key reaction was a reduction of oxetanyl nitriles with lithium aluminum hydride. The mechanism, scope, and scalability of this method were studied. The reaction proceeded via an "invisible" intermediate 4 (Scheme 2) that was caught by backsynthesis. Crystallographic analysis revealed a high similarity of the 3-azabicyclo[3. 1.1]heptane core with the pyridine ring. This scaffold was also incorporated into the Rupatadine drug instead of the pyridine ring which led to dramatic improvement of all physicochemical parameters: solubility, metabolic stability, and lipophilicity.