Harnessing sterically controlled and rare-earth-catalyzed chemodivergent (3 + 3) annulations between enamines and Achmatowicz rearrangement products (ARPs), we provide practical methods for efficiently constructing two types of highly functionalized, three-dimensional, and rigid bicyclic scaffolds─7-oxa-2-azabicyclo3.3.1non-3-enes and 3-oxabicyclo3.3.1non-6-enes. Enantiopure products are also synthesized from readily accessed enantiopure ARPs.
Li et al. (2026) studied this question.