Diastereo‐divergentsynthesis of saturatedazaheterocycles has been achieved by tBuOK‐mediatedhydroamination of alkenylhydrazones. DFT calculations suggested that the cation–π interactions between a potassium cation and aryl substituents on hydrazones give rise to 2,5‐cis selectivity in pyrrolidines, which were synthesized by the reaction of γ,δ‐unsaturated N‐benzyl hydrazones. By contrast, 2,5‐trans