Organophotocatalytic Single-Step Oximation through an Olefin [4 + 2] Annulation

Oximino derivatives are versatile synthetic intermediates, yet conventional routes to tetralone oximes remain step-intensive and inefficient. Herein, we disclose a photocatalytic single-step oximation enabled by a formal [4 + 2] annulation between two alkenes. This strategy exploits the unique reactivity of the nitric oxide radical to simultaneously forge the tetralin core and install the oxime functionality. The transformation proceeds under mild, metal-free conditions, displays broad functional group tolerance, and is readily scalable. Its synthetic utility is further highlighted by the construction of complex fused ring systems and the late-stage oximation of bioactive molecules.