Total Synthesis and Characterization of 7‑Hypoquinuclidonium Tetrafluoroborate and 7‑Hypoquinuclidone BF₃ Complex

Derivatives of the fully twisted bicyclic amide 7-hypoquinuclidone are synthesized using a Schmidt–Aubé reaction. Their structures were unambiguously confirmed by X-ray diffraction analysis and extensive spectroscopic characterization. Furthermore, the stability and chemical reactivity of these anti-Bredt amides are investigated. 7-Hypoquinuclidonium tetrafluoroborate is shown to decompose to a unique nitrogen bound amide–BF₃ complex of 7-hypoquinuclidone under anhydrous conditions and to react instantaneously with water making it one of the most reactive amides known to date.