Visible‐Light Catalyzed [1+2+2] Cycloaddition Reactions Enabled by the Formation of Methylene Nitrones.

Nitrones are key intermediates in organic synthesis. Herein, we report the first photo‐redox synthesis of methylene nitrone intermediates from nitroarenes and arylamines. The highly reactive methylene nitrones are in situ trapped by alkenes to afford various isoxazolidines. This three‐component reaction features the use of N,N‐dimethylanilines or N‐aryl glycines as C1 building blocks, which allow for the one‐pot formal [1+2+2] cycloaddition from simple starting materials. A wide range of useful isoxazolidines can be obtained under mild conditions with moderate to good yields. Mechanistic investigations support the formation of methylene nitrone via selective N−CH3 bond cleavage and methylene transfer. [ABSTRACT FROM AUTHOR]