Divergent Functionalization of 3‐methyleneisoindolin‐1‐ones Enabled by Visible‐Light Photoredox‐Catalysis

ABSTRACT

We present a redox‐neutral strategy for the difunctionalization and C(sp ² )–H alkylation of 3‐methyleneisoindolin‐1‐ones using alkyl NHP esters as alkyl‐radical precursors under visible‐light irradiation. In the presence of alcohols, this approach affords difunctionalized products, while in the presence of a base, it yields C(sp ² )–H alkylation products. The protocol offers several advantages, including metal‐free, mild reaction conditions, a broad substrate scope, and compatibility with late‐stage modification of pharmaceutically relevant molecules. Preliminary mechanistic investigations, such as Stern–Volmer quenching experiments, support an oxidative‐quenching catalytic pathway and radical‐clock, and EPR studies confirm the involvement of alkyl radicals.