Synthesis of Alkylsulfonyl‐Substituted Indolo[2,1‐a]Isoquinolines via Photoredox‐Catalyzed Radical‐Cascade Addition/Sulfonylation/Cyclization with DABCO ⋅ (SO2)2 and Thianthrenium Salts

Abstract A direct, visible‐light‐mediated, radical‐cascade addition/sulfonylation/cyclization reaction with DABCO ⋅ (SO 2 ) 2 and thianthrenium salts is reported herein. This protocol provides operationally‐convenient access to various sulfonated functionalized indole [2,1‐a] isoquinolines under mild conditions. This transformation features high functional‐group tolerance, operational ease, and broad substrate scope. Preliminary studies reveal that the method undergoes a radical pathway. magnified image