Photocatalytic Aza‐Heck Cyclization/Sulfonylation/Benzylation Cascade of γ , δ ‐Unsaturated Oxime Esters for the Construction of Sulfone‐Containing Frameworks

The rapid development of SO 2 insertion strategies for the construction of sulfone frameworks has attracted increasing attention. However, methods involving indirect SO 2 incorporation remain limited due to competing direct radical insertion and undesired nonsulfonylation side reactions. Herein, we report a photocatalytic Aza‐Heck cyclization/sulfonylation/benzylation cascade of γ , δ ‐unsaturated oxime esters for the construction of sulfone‐containing frameworks. This process generates iminyl radicals from unsaturated oxime esters and benzylic radicals from p ‐methylphenol ( p ‐cresol) derivatives via photoredox catalysis. The resulting iminyl radical undergoes intramolecular Aza‐Heck cyclization, followed by preferential trapping with SO 2 to form a sulfonyl radical, which subsequently couples with the benzylic radical to afford the sulfone products. This protocol achieves selective sulfonylation of the oxime ester while suppressing nonsulfonylation processes. Notably, the p ‐cresol derivative serves both as the benzylation partner and as a hydrogen atom transfer (HAT) reagent. Furthermore, the photoredox system plays a dual role by promoting the reduction of the oxime ester and the oxidation of the phenol, thereby improving both reaction efficiency and step economy.