Photoinduced Electron Donor‐Acceptor Complex‐Driven Radical Cascade Strategy Toward Sulfonylated Pyrazolones

An efficient visible‐light‐induced arylsulfonylative radical cascade cyclization of N ′‐arylidene‐ N ‐acryloylhydrazides with diaryliodonium salts and DABSO has been developed, providing straightforward access to structurally diverse arylsulfonylated pyrazolones. The transformation proceeds photocatalyst‐free, without external base, and under mild reaction conditions with good functional group tolerance. Mechanistic investigations suggest a possible interaction between diaryliodonium salts and DABSO under visible‐light irradiation, potentially facilitating the generation of arylsulfonyl radicals. This work demonstrates the applicability of diaryliodonium salt/DABSO electron donor‐acceptor (EDA) chemistry to the efficient synthesis of arylsulfonylated pyrazolones under photoinduced conditions.